Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/23/14


AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1138 AM MDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1028 AM MDT SAT JUN 21 2014 CONSIDERABLE AMOUNT OF MID/HIGH LEVEL CLOUD (ASSOCIATED WITH EMBEDDED WEAK SHORT WAVES) STREAMING ACROSS THE REGION TODAY. AS DEEP LAYERED MIXING OCCURS...EXPECT THE CLOUD LAYER TO "THIN" OUT IN THE AFTERNOON. MORNING CLOUD COVER MAY HAVE A MINOR IMPACT ON FORECASTED HIGH TEMPS BY 1-2 DEGREES...BUT RECOVERY BENEATH THE JUNE SUN CAN BE VERY QUICK. CONVECTIVE POTENTIAL BETWEEN THE RAP AND NAM12 IS SIGNIFICANT...WITH THE WETTER NAM12 SUGGESTING SOME ACTIVITY HUGGING THE HIGHER TERRAIN. THE HIGHER RESOLUTION NAMDNG25 IS NOT AS WET. CLOUD COVER TYPICALLY TEMPERS THE CONVECTIVE POTENTIAL...COMBINED WITH PERCIPITABLE WATER AT FOUR TENTHS OF AN INCH (PER 12Z GJT SOUNDING) AND MOIST LAYER AT OR ABOVE 500 MB...NOT INCLINED TO INCREASE THE CHANCE FOR STORMS THIS AFTERNOON. A LIGHTNING STRIKE OR TWO MAY OCCUR OVER THE UINTA MOUNTAINS AND ALONG THE COLORADO SPINE. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 343 AM MDT SAT JUN 21 2014 TODAY...A WEAK SHORTWAVE TROUGH WELL SEEN AT 700 MB AND 500 MB...AND SATELLITE IMAGES...WILL BRING MID AND HI LEVEL MOISTURE TO THE AREA THIS MORNING AND AFTERNOON. EXPECT ISOLATED THUNDERSTORMS OVER THE HIGHER PEAKS FROM EARLY AFTERNOON UNTIL SUNSET. MAX TEMPS WILL CONTINUE MOVING UPWARD WITH MOST AREAS REACHING HIGHS A FEW DEGREES ABOVE NORMAL. TONIGHT AND SUNDAY...FAST...PROGRESSIVE...WESTERLY FLOW STAYS IN PLACE TO CLOSE OUT THE WEEKEND ACROSS THE CONUS. THERE WILL BE A SERIES OF WAVES TREKKING OUT OF THE EASTERN PACIFIC INTO THE INTERMOUNTAIN WEST THROUGH THIS FLOW. DYNAMIC TROP PRESSURE FIELDS INDICATE THESE WILL BE WEAKENING AS THEY MOVE EAST TOWARD OUR CWA SO LARGE SCALE ASCENT LOOKS UNORGANIZED. THE MOISTURE COMING OUT OF THE PACIFIC WITH THE WAVES IS NOT IMPRESSIVE EITHER AND SEEMS TO REMAIN AOA 500 MB. THERE IS A HINT OF JET INTERACTION WITH THE APPROACHING WAVE OVERNIGHT. CONFIDENCE NOT HIGH BUT THERE COULD BE ISOLATED NOCTURNAL CONVECTION DEVELOP OVERNIGHT...POPS VERY LIMITED AS ACCAS IS MORE LIKELY IN THE HIGHLY MIXED ATMOSPHERE. TEMPERATURES REMAIN SOMEWHAT MILD WITH HIGH CLOUDS OVERNIGHT. H7 TEMPS AND GUIDANCE SUGGEST A SLIGHT COOL DOWN FOR SUNDAY WITH WEAK CAA BEHIND THE WAVE MOVING THROUGH SUNDAY. THIS MAY BE THE PERIOD WITH THE HIGHEST POPS OF THE FORECAST...BUT MAINLY OVER THE EASTERN DIVIDE MOUNTAINS. LOOKING AT SOUNDINGS AND DCAPE FORECASTS GUSTY WINDS WILL BE MORE LIKELY THAN RAINFALL. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 343 AM MDT SAT JUN 21 2014 SUNDAY NIGHT INTO MONDAY...PV FIELDS SHOW YET ANOTHER WEAK WAVE PASSING THROUGH THE ROCKIES SUNDAY NIGHT...BUT WITH LITTLE TO NO SUPPORT. BEHIND THIS LAST WAVE THERE IS A HINT OF A BUILDING WESTERN RIDGE. THE BULK OF THE MODEL SOLUTIONS ARE QUIET MONDAY AFTERNOON OUTSIDE OF THE DIVIDE. HOWEVER THE NAM WANTS TO SWING ANOTHER BATCH OF ENERGY THROUGH DURING PEAK HEATING. DO NOT WANT TO BITE ON THIS JUST YET AS NAM SEEMS TO BE OVER EAGER TO PRODUCE CONVECTION. CLEARING SKIES SUNDAY NIGHT SHOULD LOWER OVERNIGHT LOWS A FEW DEGREES WHILE A STRONG DIURNAL REBOUND PUSHES HIGHS ON MONDAY BACK ABOVE NORMAL. MONDAY NIGHT THROUGH FRIDAY...MAINLY WEAK ZONAL FLOW SHOULD CONTINUE OVER THE AREA THRU TUE NIGHT. ON WED BOTH THE GFS AND EC SHOW A TROUGH DIGGING INTO THE GREAT BASIN AND STRENGTHENING SW WINDS ALOFT AHEAD OF THE TROUGH AND OVER THE FORECAST AREA. THE EC IS STRONGER WITH THIS SYSTEM AND CARRIES A HIGH AMPLITUDE TROUGH AND RELATIVELY STRONG SURFACE COLD FRONT THROUGH THE FORECAST AREA THU NIGHT AND FRI. THE GFS WEAKENS THE TROUGH AS IT MOVES EAST AND LIFT A BIT TO THE NE OVER THE NORTHERN ROCKIES. THE SURFACE FRONT IN THE GFS IS MUCH WEAKER AS WELL...SO THE CHANGE IN THE FORECAST AT THE END OF THE PERIOD REMAINS UNCERTAIN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1138 AM MDT SAT JUN 21 2014 LOCAL LIGHT TO MODERATE CHOP AS MID/HIGH CLOUD CLOUD LAYER HAS POCKETS OF VIRGA. THREAT OF -TSRA THROUGH 02Z WILL BE CONFINED TO THE EASTERN UINTA MOUNTAINS AND TOWARD THE COLORADO HIGH COUNTRY. VFR PREVAILS THROUGH THE FORECAST PERIOD. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...PF SHORT TERM...CC/15 LONG TERM...15/CC AVIATION...PF
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1028 AM MDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1028 AM MDT SAT JUN 21 2014 CONSIDERABLE AMOUNT OF MID/HIGH LEVEL CLOUD (ASSOCIATED WITH EMBEDDED WEAK SHORT WAVES) STREAMING ACROSS THE REGION TODAY. AS DEEP LAYERED MIXING OCCURS...EXPECT THE CLOUD LAYER TO "THIN" OUT IN THE AFTERNOON. MORNING CLOUD COVER MAY HAVE A MINOR IMPACT ON FORECASTED HIGH TEMPS BY 1-2 DEGREES...BUT RECOVERY BENEATH THE JUNE SUN CAN BE VERY QUICK. CONVECTIVE POTENTIAL BETWEEN THE RAP AND NAM12 IS SIGNIFICANT...WITH THE WETTER NAM12 SUGGESTING SOME ACTIVITY HUGGING THE HIGHER TERRAIN. THE HIGHER RESOLUTION NAMDNG25 IS NOT AS WET. CLOUD COVER TYPICALLY TEMPERS THE CONVECTIVE POTENTIAL...COMBINED WITH PERCIPITABLE WATER AT FOUR TENTHS OF AN INCH (PER 12Z GJT SOUNDING) AND MOIST LAYER AT OR ABOVE 500 MB...NOT INCLINED TO INCREASE THE CHANCE FOR STORMS THIS AFTERNOON. A LIGHTNING STRIKE OR TWO MAY OCCUR OVER THE UINTA MOUNTAINS AND ALONG THE COLORADO SPINE. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 343 AM MDT SAT JUN 21 2014 TODAY...A WEAK SHORTWAVE TROUGH WELL SEEN AT 700 MB AND 500 MB...AND SATELLITE IMAGES...WILL BRING MID AND HI LEVEL MOISTURE TO THE AREA THIS MORNING AND AFTERNOON. EXPECT ISOLATED THUNDERSTORMS OVER THE HIGHER PEAKS FROM EARLY AFTERNOON UNTIL SUNSET. MAX TEMPS WILL CONTINUE MOVING UPWARD WITH MOST AREAS REACHING HIGHS A FEW DEGREES ABOVE NORMAL. TONIGHT AND SUNDAY...FAST...PROGRESSIVE...WESTERLY FLOW STAYS IN PLACE TO CLOSE OUT THE WEEKEND ACROSS THE CONUS. THERE WILL BE A SERIES OF WAVES TREKKING OUT OF THE EASTERN PACIFIC INTO THE INTERMOUNTAIN WEST THROUGH THIS FLOW. DYNAMIC TROP PRESSURE FIELDS INDICATE THESE WILL BE WEAKENING AS THEY MOVE EAST TOWARD OUR CWA SO LARGE SCALE ASCENT LOOKS UNORGANIZED. THE MOISTURE COMING OUT OF THE PACIFIC WITH THE WAVES IS NOT IMPRESSIVE EITHER AND SEEMS TO REMAIN AOA 500 MB. THERE IS A HINT OF JET INTERACTION WITH THE APPROACHING WAVE OVERNIGHT. CONFIDENCE NOT HIGH BUT THERE COULD BE ISOLATED NOCTURNAL CONVECTION DEVELOP OVERNIGHT...POPS VERY LIMITED AS ACCAS IS MORE LIKELY IN THE HIGHLY MIXED ATMOSPHERE. TEMPERATURES REMAIN SOMEWHAT MILD WITH HIGH CLOUDS OVERNIGHT. H7 TEMPS AND GUIDANCE SUGGEST A SLIGHT COOL DOWN FOR SUNDAY WITH WEAK CAA BEHIND THE WAVE MOVING THROUGH SUNDAY. THIS MAY BE THE PERIOD WITH THE HIGHEST POPS OF THE FORECAST...BUT MAINLY OVER THE EASTERN DIVIDE MOUNTAINS. LOOKING AT SOUNDINGS AND DCAPE FORECASTS GUSTY WINDS WILL BE MORE LIKELY THAN RAINFALL. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 343 AM MDT SAT JUN 21 2014 SUNDAY NIGHT INTO MONDAY...PV FIELDS SHOW YET ANOTHER WEAK WAVE PASSING THROUGH THE ROCKIES SUNDAY NIGHT...BUT WITH LITTLE TO NO SUPPORT. BEHIND THIS LAST WAVE THERE IS A HINT OF A BUILDING WESTERN RIDGE. THE BULK OF THE MODEL SOLUTIONS ARE QUIET MONDAY AFTERNOON OUTSIDE OF THE DIVIDE. HOWEVER THE NAM WANTS TO SWING ANOTHER BATCH OF ENERGY THROUGH DURING PEAK HEATING. DO NOT WANT TO BITE ON THIS JUST YET AS NAM SEEMS TO BE OVER EAGER TO PRODUCE CONVECTION. CLEARING SKIES SUNDAY NIGHT SHOULD LOWER OVERNIGHT LOWS A FEW DEGREES WHILE A STRONG DIURNAL REBOUND PUSHES HIGHS ON MONDAY BACK ABOVE NORMAL. MONDAY NIGHT THROUGH FRIDAY...MAINLY WEAK ZONAL FLOW SHOULD CONTINUE OVER THE AREA THRU TUE NIGHT. ON WED BOTH THE GFS AND EC SHOW A TROUGH DIGGING INTO THE GREAT BASIN AND STRENGTHENING SW WINDS ALOFT AHEAD OF THE TROUGH AND OVER THE FORECAST AREA. THE EC IS STRONGER WITH THIS SYSTEM AND CARRIES A HIGH AMPLITUDE TROUGH AND RELATIVELY STRONG SURFACE COLD FRONT THROUGH THE FORECAST AREA THU NIGHT AND FRI. THE GFS WEAKENS THE TROUGH AS IT MOVES EAST AND LIFT A BIT TO THE NE OVER THE NORTHERN ROCKIES. THE SURFACE FRONT IN THE GFS IS MUCH WEAKER AS WELL...SO THE CHANGE IN THE FORECAST AT THE END OF THE PERIOD REMAINS UNCERTAIN. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 343 AM MDT SAT JUN 21 2014 VFR CONDITIONS WILL PREVAIL ACROSS THE AREA AND AT ALL AIRPORTS AND TAF SITES THROUGH TONIGHT...WITH THE EXCEPTION OF ISOLATED THUNDERSTORMS BETWEEN ABOUT 20Z AND 03Z OVER THE RIDGES. THESE WILL BE RELATIVELY SHORT-LIVED WITH GUSTY WINDS BEING THE MAIN IMPACTOR ON AVIATION. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...PF SHORT TERM...CC/15 LONG TERM...15/CC AVIATION...CC
REMAINING FORECAST DISCUSSION WILL BE ISSUED SHORTLY...

&& .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * VCTS TRENDING TO ISOLATED-SCATTERED TSRA BETWEEN 20-23Z. * LGT WINDS...GENERALLY SE ARND 8-10KT. THUNDERSTORMS MAY BRIEFLY BECOME VRB DIR/SPEEDS IN AND ARND THUNDERSTORMS. * FOG REDEVELOPS AFT 6Z TONIGHT...VSBY COULD EASILY BE REDUCED TO NEAR IFR CONDS. BEACHLER //DISCUSSION...UPDATED 18Z... VISIBLE IMAGERY THIS AFTN SHOWS MOST CLOUD COVER CONFINED TO NORTH OF CENTRAL IL OVER THE TAF SITES...WITH SOME ENHANCEMENT BEGINNING TO DEVELOP. RADAR RETURNS HAVE BEEN SHOWING ISO TSRA DEVELOPING AND HAVE BEEN PRODUCING SOME LIGHTNING WITH EXPECTED CONTINUE GROWTH IN SIZE AND INTENSITY OF THE THUNDERSTORMS. WINDS ARE GENERALLY FROM THE SOUTHEAST ACROSS FAR NORTHEAST IL/NORTHWEST IN...MEANWHILE JUST WEST OF THOSE SITES WINDS TURN TO SOUTHWESTERLY OR SOUTHERLY. WITH THE LACK OF A GRADIENT...SPEEDS HAVE HELD AROUND 8KT OR LESS WITH AN OCCASIONAL GUST TO 16KT. IF TSRA CAN BECOME MORE ORGANIZED...THE POTENTIAL FOR WINDS TO BECOME STRONGER IN AND ARND TSRA IS PROBABLE. THE BEST TIMING FOR INCREASED COVERAGE IN TSRA WILL BE 20-23Z FOR NORTHERN IL...THEN LINGERING TO JUST AFT 00Z ACROSS NORTHWEST IN. LATER THIS EVENING THE POTENTIAL OF AN ISO TSRA CONTINUES...HOWEVER THE CONFIDENCE IN COVERAGE AND PRECISE TIMING DECREASES. SO HAVE OPTED TO HOLD OFF ON ANY MENTION OF ADDTL TSRA THIS EVE. OVERNIGHT WINDS BECOME LGT AND VRB AGAIN...WITH THE POSSIBILITY OF FOG REDEVELOPING. AT THIS TIME CONFIDENCE IS THAT THE DENSE FOG SHOULD BE CONFINED TO LAKE MICHIGAN. ALTHOUGH THAT BEING SAID MOST TAF SITES WILL STILL SEE VSBYS DROP TO ARND 2-3SM AND POSSIBLY RFD/DPA COULD DIP TO ARND 1SM OVERNIGHT. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN TSRA DEVELOPING...MEDIUM CONFIDENCE IN PRECISE TIMING/COVERAGE OF TSRA BETWEEN 19-23Z. * MEDIUM/HIGH CONFIDENCE IN WIND DIR/SPEED. * MEDIUM/HIGH CONFIDENCE IN FOG REDEVELOPING...LOW CONFIDENCE IN PRECISE TIMING. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE TSRA. MONDAY...TSRA LIKELY. TUESDAY THROUGH THURSDAY...PERIOD CHANCES FOR TSRA/SHRA. THURSDAY NIGHT AND FRIDAY...VFR. WX NIL. KREIN && .MARINE... 234 PM CDT GENERALLY LIGHT WIND REGIME OUTSIDE OF THUNDERSTORM INDUCED WINDS TO CONTINUE THOUGH MONDAY NIGHT WHEN A COLD FRONT WILL SWEEP ACROSS THE LAKE BRINGING DRYER CONDITIONS AND NORTHERLY FLOW BY TUESDAY. UNTIL THEN... EXPECT AREAS OF DENSE FOG TO PERSIST OVER THE LAKE WITH WINDS GENERALLY REMAINING AT OR BELOW 20 KTS AND WAVES AT OR BELOW 3 FEET. WINDS AND WAVES WILL BE HIGHER NEAR THUNDERSTORMS. A RIDGE OF HIGH PRESSURE FROM JAMES BAY TO THE CENTRAL GREAT LAKES WILL REMAIN NEARLY STATIONARY TONIGHT AND THEN GRADUALLY DRIFT EAST SUNDAY. MEANWHILE WEAK LOW PRESSURE OVER WISCONSIN WILL SLIDE SOUTHEAST ALONG A NEARLY STATIONARY FRONTAL BOUNDARY ACROSS NORTH CENTRAL ILLINOIS TO SOUTHEAST ILLINOIS OVERNIGHT AND DISSIPATE. WEAK LOW PRESSURE OVER THE CENTRAL PLAINS WILL BECOME BETTER ORGANIZED AS IT DOES AND MOVE EAST. THIS LOW WILL REACH CENTRAL IOWA BY DAYBREAK MONDAY AND MOVE TO THE EASTERN UPPER PENINSULA OF MICHIGAN BY OVERNIGHT MONDAY INTO TUESDAY. A WEAK COLD FRONT ASSOCIATED WITH THIS LOW WILL THEN SWEEP ACROSS THE LAKE LATE MONDAY NIGHT INTO TUESDAY...TURNING WINDS FROM SOUTHERLY TO NORTHERLY. BROAD HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WEDNESDAY LASTING INTO THURSDAY. ED F && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
100 PM CDT SAT JUN 21 2014 .MESOSCALE DISCUSSION... UPDATED...1029 AM CDT CONVECTIVE POTENTIAL FOR EARLY TO MID AFTERNOON TODAY WITH A THREAT REMAINING FOR STRONG TO SEVERE WEATHER...PRIMARILY A HIGH WIND THREAT...ACROSS NORTH CENTRAL ILLINOIS AND POSSIBLY NORTHWEST INDIANA. CURRENT RADAR IMAGERY DEPICTING ISOLATED SHOWER ACTIVITY ACROSS NORTH CENTRAL AND NORTHEAST ILLINOIS SLIDING EAST OUT AHEAD OF WEAKENING WAA WING STRETCHING SOUTH THROUGH THE AREA. DONT ANTICIPATE ANY FURTHER DEVELOPMENT WITH THESE SHOWERS THIS MORNING WITH THE CURRENT ISOLATED COVERAGE REMAINING THE SAME NOR DO I EXPECT MUCH IN TERMS OF ANY THUNDER OUTSIDE OF A FEW RUMBLES OF THUNDER...AS THIS PRECIP IS BEING WEAKLY FORCED AND IN THE PRESENCE OF A MORE STABLE ENVIRONMENT. OUTSIDE OF THIS DEVELOPMENT...EXPECT THE REMAINDER OF THE MORNING TO REMAIN DRY WHILE LOW STRATUS FURTHER DIMINISHES THROUGH MID DAY WITH MORE AREAS OBSERVING PARTLY CLOUDY TO PARTLY SUNNY CONDITIONS. SHIFT FOCUS TO MAIN THUNDERSTORM THREAT FOR THIS AFTERNOON...AND POSSIBLY INTO THE EARLY EVENING...FOR THE ENTIRE AREA OF NORTH CENTRAL/NORTHEAST ILLINOIS AND NORTHWEST INDIANA. THE THUNDERSTORM POTENTIAL WILL BE TIED TO APPROACHING MCV AND LINGERING FRONTAL BOUNDARY SITUATED FROM NORTHWEST ILLINOIS BACK SOUTHEAST THROUGH EAST CENTRAL ILLINOIS...AND INTO NORTHWEST INDIANA. AS THIS VIGOROUS SYSTEM PUSHES EAST INTO NORTHERN ILLINOIS AND SOUTHERN WISCONSIN BY MID DAY...IT WILL BE ENCOUNTERING AN INCREASINGLY UNSTABLE ENVIRONMENT WHICH IS ALREADY OCCURRING OVER WESTERN ILLINOIS WITH LATEST RAP ANALYSIS SHOWING STEADILY STEEPENING LOW LEVEL LAPSE RATES. LIMITING FACTORS SUCH HIGH CIN IN PLACE WILL ERODE THROUGH MID DAY WHILE CURRENT MODERATE INSTABILITY AXIS FROM NORTHWEST ILLINOIS SOUTH TO WEST CENTRAL ILLINOIS BEGINS SPREADING EASTWARD. SHORT TERM GUIDANCE IN FAIR AGREEMENT WITH THE TIMING OF THIS OCCURRENCE AROUND THE 19Z TO 20Z TIME FRAME...AND WILL BE OCCURRING AS LARGE SCALE ASCENT WITH APPROACHING SYSTEM SPREADS EAST. MOST CURRENT GUIDANCE THIS MORNING IN AGREEMENT WITH DEVELOPING PRECIP ACROSS THE CWA THIS AFTERNOON AND ALTHOUGH I DO AGREE WITH THE IDEA/SOLUTION...I WONDER IF THE COVERAGE WILL BE AS EXTENSIVE AS IS BEING ADVERTISED. THIS CONCERN IS TIED TO LOW LEVEL CONVERGENCE POTENTIAL WITH WHICH CURRENT GUIDANCE IS APPEARING TO BE OVERDOING AT THIS TIME. IF THIS OVERESTIMATE CONTINUES...COVERAGE MAY NOT BE AS EXTENSIVE. NONETHELESS...DESPITE THIS LIMITING FACTOR FEEL THAT LARGE SCALE SUPPORT IN A MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT SHOULD BE ENOUGH TO AT LEAST DEVELOP SCATTERED DEVELOPMENT THIS AFTERNOON. CURRENT ASSESSMENT WOULD PLACE HIGHER THREAT FOR STRONG TO SEVERE WEATHER ACROSS THE WEST AND SOUTHWEST CWA WHERE BETTER INSTABILITY WILL RESIDE...BUT AS THE STABLE ENVIRONMENT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA BECOMES MORE UNSTABLE LATER THIS AFTERNOON FEEL THAT ALL AREAS COULD POTENTIALLY HAVE THE SAME THREAT. SO DONT WANT TO REALLY POINT OUT ONE AREA OVER THE OTHER AT THIS TIME...BUT WILL CONTINUE TO MONITOR THIS POTENTIAL WITH AN UPDATED AFD WITH LATEST THINKING LIKELY BY MID DAY. AREAS ALONG AND WEST OF INTERSTATE 39 COULD OBSERVE SCATTERED STRONG TO SEVERE THUNDERSTORM DEVELOPMENT BY 19-20Z...SPREADING EAST THROUGH REMAINING AREAS IN NORTH CENTRAL ILLINOIS AND THEN NORTHEAST ILLINOIS IN THE 20-22Z TIME FRAME. CONFIDENCE IS LOWER WITH REGARD TO STRONG/SEVERE THREAT IN NORTHWEST INDIANA...BUT IF THIS WERE TO SPREAD EAST INTO THESE AREAS IT WOULD BE IN THE 22-23Z TIME WINDOW. THE MAIN SEVERE THREAT TODAY WILL BE DAMAGING WIND GUSTS...BUT HAIL COULD POSSIBLY BECOME AN ISSUE ESPECIALLY IN ANY OF THE MORE DEVELOPED THUNDERSTORMS. RODRIGUEZ && .DISCUSSION... 339 AM CDT THE BASIC PATTERN THAT HAS NOW BEEN IN PLACE FOR NEARLY A WEEK WILL CONTINUE THROUGH MONDAY...WHICH MEANS NUMEROUS FORECAST CHALLENGES ON THIS SUMMER SOLSTICE. MORNING FOG AND STRATUS IS FIRST IN THE TIMELINE FOLLOWED BY ITS IMPACT ON TEMPERATURES AND DESTABILIZATION FOR THUNDERSTORM COVERAGE THIS AFTERNOON. QUANTIFYING ANY SEVERE POTENTIAL ALSO NEEDED TO BE ASSESSED. FINALLY...CONTINUED THUNDERSTORM CHANCES...ESPECIALLY THROUGH MONDAY NIGHT...ROUNDED OUT THE FORECAST THIS MORNING. FOG AND TEMPERATURES... DENSE FOG THAT HAD EXPANDED INLAND LAST EVENING BEHIND THE IMPRESSIVE LAKE BREEZE,,,WHICH AS OF 330 AM HAS FINALLY STALLED NEAR INTERSTATE 74...CONTINUES OVER LAKE ADJACENT COUNTIES. WEB CAMS AND REPORTS INDICATE THIS IS MOST DENSE NEAR THE LAKE SHORE AND WILL CONTINUE THE DENSE FOG ADVISORY THROUGH 9 AM...WITH POTENTIALLY SOME SHORELINE LOCALES DOWN TO A FEW HUNDRED FEET VISIBILITY. VAD PROFILES INDICATE THE NORTHEAST FLOW IS ABOUT 2000-3000FT THICK AND AN AMDAR SOUNDING FROM LAST EVE INDICATES SATURATION IS ONLY ABOUT HALF OF THAT. WITH THIS BEING THE LONGEST DAYLIGHT OF THE YEAR ONE WOULD THINK WE COULD MIX THROUGH THIS QUICKLY...ESPECIALLY WITH THE SOURCE FLOW OFF THE LAKE HAVING CONSIDERABLY WEAKENED. THE ONE CONCERN WITH THAT IS CONVECTIVE DEBRIS CLOUDS ARE SPREADING OVER THIS WHICH WILL FURTHER INSULATE THIS MORNING. SO THAT WILL NEED TO BE WATCHED. HAVE ADJUSTED FORECAST HOURLY TEMPERATURES TO SLOW THE RATE OF WARMING CONSIDERABLY AND THAT LED TO COOLER HIGH TEMPERATURES. WHILE TEMPERATURES WILL COULD DEPEND ON CONVECTIVE INITIATION TIME AND COVERAGE /SEE BELOW/...FEEL THAT UNDERCUTTING GUIDANCE AND CLIMO WAS THE WAY TO GO...OWING TO THE MUCH COOLER-THAN-NORMAL WATER TEMPERATURES OF LAKE MICHIGAN WHICH FED THIS AREA OF FOG/STRATUS. THUNDERSTORM POTENTIAL... MULTIPLE LOW AMPLITUDE UPPER DISTURBANCES WILL TRANSLATE EASTWARD TODAY ACROSS A BELT OF ZONAL FLOW EXTENDING FROM THE CENTRAL PLAINS OVER THE FORECAST AREA. THIS IS ON THE NORTHERN END OF CONTINUED HIGH PRECIPITABLE WATER AND UNSTABLE AIR. ONGOING CONVECTION ACROSS WESTERN AND CENTRAL IA AS OF 330 AM HAS WEAKENED CONSIDERABLY WITH ONLY MARGINAL MOISTURE TRANSPORT FEEDING IT. DOES LOOK LIKE THE SHORT WAVE MAY BE CONVECTIVELY ENHANCED WITH A POSSIBLE MCV AND TIMING THAT FEATURE SEEMS KEY FOR OUR MAIN STORM CHANCES TODAY. THE SUITE OF GUIDANCE VARIES CONSIDERABLY AND GIVEN THAT AND SIMPLY THE TRICKY SYNOPTIC POSITION WE ARE IN...AS WELL AS THE MESOSCALE FACTOR OF THE CURRENT FOG/STRATUS...CONFIDENCE IS LOW ON THUNDERSTORM COVERAGE AND TIMING TODAY. INCREASE POPS GRADUALLY THIS MORNING WITH SOME SCATTERED ELEVATED STORMS POSSIBLE IN NORTH CENTRAL IL...AND THEN MORE SO EARLY THIS AFTERNOON AS MID-LEVEL FEATURE PASSES OVER THE FORECAST AREA. CONVECTIVE TEMPERATURES LOOK TO BE AROUND 80 DEGREES AND NOT CERTAIN IF PARTS OF NORTHEAST IL WILL REACH THAT...SO KEEP HIGHER POPS MAINLY ALONG AND SOUTH OF THE MORE STABLE LOW-LEVEL AIR IN PLACE /JUST SOUTH OF CHICAGO/. THIS ALSO IS WHERE LOW-LEVEL CONVERGENCE EXISTS...ALBEIT WITH AWFULLY WEAK FLOW. SO AM NOT ENVISIONING GREAT COVERAGE OF AFTERNOON STORMS BUT ENOUGH TO SUPPORT 40 TO 50 PERCENT POPS AND HAVE GONE WITH SCATTERED WORDING. CONVECTIVE CELLS POSSIBLY BECOMING MORE MULTICELL WITH SMALL-SCALE COLD POOLS ARE THE PROBABLE EVOLUTION. MID-LEVEL LAPSE RATES ARE POOR AND THE THERMODYNAMIC ENVIRONMENT LOOKS ALREADY HINDERED BY THE INVERSION IN PLACE...SO NOT EXPECTING MUCH FOR HAIL...BUT SOME OF THE MORE ORGANIZED STORMS COULD HAVE AN ISOLATED WIND THREAT DUE TO PRECIP LOADING AND SOME HIGHER DOWNDRAFT CAPE INDICATED BY A FEW HIGH-RES MODELS. THIS WOULD SEEM A LITTLE MORE FAVORED SOUTH OF A ROCKFORD TO RENSSELAER LINE. TONIGHT... GRADUAL WARM AIR ADVECTION AND ANOTHER ONE OR TWO MINOR IMPULSES MAY CONTINUE SEPARATE SCATTERED STORMS FROM THE EARLIER ACTIVITY AFTER DARK...NAMELY OVER THE WESTERN AND SOUTHERN FORECAST AREA. IN ADDITION...LIGHT WIND FLOW ELSEWHERE MAY ALLOW STRATUS AND/OR FOG TO DEVELOP. THIS AGAIN WOULD BE ESPECIALLY FAVORED NEAR THE LAKE SHORE. HAVE ADDED FOG MENTION ONCE AGAIN IN CHICAGO BEGINNING LATER THIS EVE. SUNDAY AND MONDAY... WARM AIR ADVECTION IS FORECAST TO INCREASE ON SUNDAY WITH THE CHANCE FOR SCATTERED STORMS. MODEL GUIDANCE IS IN GOOD AGREEMENT WITH NOTHING OVERLY ORGANIZED...SO HAVE KEPT POPS NEAR WHERE THEY WERE. TEMPERATURES AGAIN WILL BE TRICKY...REMAINING MUCH COOLER NEAR THE LAKE AND POTENTIALLY HAVING TO FIGHT THROUGH MORNING STRATUS. HEIGHT FALLS ARE EXPECTED TO SPREAD INTO THE FORECAST AREA ON MONDAY AND THAT LOOKS TO PRESENT THE BEST CHANCE FOR STORMS INCLUDING INTO MONDAY NIGHT AS THE FRONT APPROACHES AND MOVES THROUGH. PRECIPITABLE WATER IS ANTICIPATED TO CLIMB BACK TO NEAR 1.75 INCHES WITH STRONG DEEP LAYER MOISTURE CONVERGENCE. WHILE THE DEEP LAYER SHEAR IS NOT PARTICULARLY STRONG OWING TO THE MARGINAL MID-LEVEL FLOW...ENOUGH INSTABILITY AND FOCUS IS PRESENT WITH THE SYNOPTIC PATTERN TO WARRANT A HIGHER LIKELIHOOD FOR RAIN. THE MORE SUN AND GREATER INSTABILITY ON MONDAY THEN THE LIKELY BETTER CHANCES FOR SOME SEVERE POSSIBILITY. TUESDAY AND BEYOND... LONG RANGE GUIDANCE IS IN DECENT AGREEMENT WITH RAIN CHANCES DIMINISHING THROUGH TUESDAY WITH THE AIR MASS BEING SOMEWHAT SCOURED OUT SEEING DEW POINTS FORECAST DOWN INTO THE LOWER 60S. THE UPPER AND MID-LEVEL PATTERN WILL KEEP US SOMEWHAT UNSETTLED...THOUGH DEEP MOISTURE AND INSTABILITY WILL BE LESS. HAVE A LOT OF SMALL POPS BUT THE OVERALL PATTERN TUE-THU DOES NOT LOOK CONDUCIVE FOR HIGH IMPACT WEATHER. ONSHORE FLOW ON A FEW MIDWEEK DAYS LOOKS TO KEEP TEMPERATURES ONCE AGAIN QUITE A BIT COOLER NEAR THE LAKE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * VCTS TRENDING TO ISOLATED-SCATTERED TSRA BETWEEN 20-23Z. * LGT WINDS...GENERALLY SE ARND 8-10KT. THUNDERSTORMS MAY BRIEFLY BECOME VRB DIR/SPEEDS IN AND ARND THUNDERSTORMS. * FOG REDEVELOPS AFT 6Z TONIGHT...VSBY COULD EASILY BE REDUCED TO NEAR IFR CONDS. BEACHLER //DISCUSSION...UPDATED 18Z... VISIBLE IMAGERY THIS AFTN SHOWS MOST CLOUD COVER CONFINED TO NORTH OF CENTRAL IL OVER THE TAF SITES...WITH SOME ENHANCEMENT BEGINNING TO DEVELOP. RADAR RETURNS HAVE BEEN SHOWING ISO TSRA DEVELOPING AND HAVE BEEN PRODUCING SOME LIGHTNING WITH EXPECTED CONTINUE GROWTH IN SIZE AND INTENSITY OF THE THUNDERSTORMS. WINDS ARE GENERALLY FROM THE SOUTHEAST ACROSS FAR NORTHEAST IL/NORTHWEST IN...MEANWHILE JUST WEST OF THOSE SITES WINDS TURN TO SOUTHWESTERLY OR SOUTHERLY. WITH THE LACK OF A GRADIENT...SPEEDS HAVE HELD AROUND 8KT OR LESS WITH AN OCCASIONAL GUST TO 16KT. IF TSRA CAN BECOME MORE ORGANIZED...THE POTENTIAL FOR WINDS TO BECOME STRONGER IN AND ARND TSRA IS PROBABLE. THE BEST TIMING FOR INCREASED COVERAGE IN TSRA WILL BE 20-23Z FOR NORTHERN IL...THEN LINGERING TO JUST AFT 00Z ACROSS NORTHWEST IN. LATER THIS EVENING THE POTENTIAL OF AN ISO TSRA CONTINUES...HOWEVER THE CONFIDENCE IN COVERAGE AND PRECISE TIMING DECREASES. SO HAVE OPTED TO HOLD OFF ON ANY MENTION OF ADDTL TSRA THIS EVE. OVERNIGHT WINDS BECOME LGT AND VRB AGAIN...WITH THE POSSIBILITY OF FOG REDEVELOPING. AT THIS TIME CONFIDENCE IS THAT THE DENSE FOG SHOULD BE CONFINED TO LAKE MICHIGAN. ALTHOUGH THAT BEING SAID MOST TAF SITES WILL STILL SEE VSBYS DROP TO ARND 2-3SM AND POSSIBLY RFD/DPA COULD DIP TO ARND 1SM OVERNIGHT. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN TSRA DEVELOPING...MEDIUM CONFIDENCE IN PRECISE TIMING/COVERAGE OF TSRA BETWEEN 19-23Z. * MEDIUM/HIGH CONFIDENCE IN WIND DIR/SPEED. * MEDIUM/HIGH CONFIDENCE IN FOG REDEVELOPING...LOW CONFIDENCE IN PRECISE TIMING. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE TSRA. MONDAY...TSRA LIKELY. TUESDAY THROUGH THURSDAY...PERIOD CHANCES FOR TSRA/SHRA. THURSDAY NIGHT AND FRIDAY...VFR. WX NIL. KREIN && .MARINE... 245 AM CDT HIGH PRESSURE CENTERED WILL SIT OVER JAMES BAY THROUGH SATURDAY NIGHT WITH WEAK RIDGING EXTENDING SOUTH ACROSS LAKE MICHIGAN TO THE LOWER MISSISSIPPI VALLEY. A WEAK STATIONARY FRONT IS DRAPED FROM NORTHERN MINNESOTA...JUST SOUTH OF THE LAKE TO THE OHIO VALLEY. WITH WARM...MOIST AIR SPREADING OVER THE COLD LAKE WATER AND SHIP OBS AND COASTAL SITES AND WEB CAMS INDICATING DENSE FOG...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR ALL OF THE OPEN WATERS AND THE ILLINOIS AND INDIANA NEARSHORE WATERS. HAVE EXTENDED THE DENSE FOG ADVISORY THROUGH SUNDAY MORNING AS THERE WILL BE LITTLE CHANGE TO THE AIRMASS OVER THE LAKE. THE EXCEPTION MAY BE THE FAR NORTHERN PORTION OF THE LAKE...WHERE WINDS SHOULD TREND A LITTLE MORE EASTERLY THAN SOUTHERLY AND ADVECT SOME DRIER AIR OVER THE LAKE...LIMITING THE DENSE FOG POTENTIAL. A COMPLEX AREA OF LOW PRESSURE OVER THE CENTRAL PLAINS WITH MULTIPLE LOW PRESSURE CENTERS...WILL GRADUALLY MOVE EAST ACROSS THE PLAINS AND TO THE WESTERN GREAT LAKES REGION BY EARLY MONDAY. A WEAK COLD FRONT SHOULD PUSH ACROSS THE LAKE MONDAY OR MONDAY NIGHT...TURNING WINDS FROM GENERALLY SOUTHERLY TO MORE NORTHERLY. AS A LARGE AREA OF HIGH PRESSURE BUILDS OUT OF CANADA TO THE UPPER GREAT LAKES TUESDAY NIGHT AND WEDNESDAY...COOLER...DRIER AIR WILL OVERSPREAD THE LAKE. THE COMBINATION OF THE FRONTAL PASSAGE AND THE BUILDING HIGH PRESSURE SHOULD BRING AN END TO THE FOG POTENTIAL. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1036 AM CDT SAT JUN 21 2014 .MESOSCALE DISCUSSION... 1029 AM CDT CONVECTIVE POTENTIAL FOR EARLY TO MID AFTERNOON TODAY WITH A THREAT REMAINING FOR STRONG TO SEVERE WEATHER...PRIMARILY A HIGH WIND THREAT...ACROSS NORTH CENTRAL ILLINOIS AND POSSIBLY NORTHWEST INDIANA. CURRENT RADAR IMAGERY DEPICTING ISOLATED SHOWER ACTIVITY ACROSS NORTH CENTRAL AND NORTHEAST ILLINOIS SLIDING EAST OUT AHEAD OF WEAKENING WAA WING STRETCHING SOUTH THROUGH THE AREA. DONT ANTICIPATE ANY FURTHER DEVELOPMENT WITH THESE SHOWERS THIS MORNING WITH THE CURRENT ISOLATED COVERAGE REMAINING THE SAME NOR DO I EXPECT MUCH IN TERMS OF ANY THUNDER OUTSIDE OF A FEW RUMBLES OF THUNDER...AS THIS PRECIP IS BEING WEAKLY FORCED AND IN THE PRESENCE OF A MORE STABLE ENVIRONMENT. OUTSIDE OF THIS DEVELOPMENT...EXPECT THE REMAINDER OF THE MORNING TO REMAIN DRY WHILE LOW STRATUS FURTHER DIMINISHES THROUGH MID DAY WITH MORE AREAS OBSERVING PARTLY CLOUDY TO PARTLY SUNNY CONDITIONS. SHIFT FOCUS TO MAIN THUNDERSTORM THREAT FOR THIS AFTERNOON...AND POSSIBLY INTO THE EARLY EVENING...FOR THE ENTIRE AREA OF NORTH CENTRAL/NORTHEAST ILLINOIS AND NORTHWEST INDIANA. THE THUNDERSTORM POTENTIAL WILL BE TIED TO APPROACHING MCV AND LINGERING FRONTAL BOUNDARY SITUATED FROM NORTHWEST ILLINOIS BACK SOUTHEAST THROUGH EAST CENTRAL ILLINOIS...AND INTO NORTHWEST INDIANA. AS THIS VIGOROUS SYSTEM PUSHES EAST INTO NORTHERN ILLINOIS AND SOUTHERN WISCONSIN BY MID DAY...IT WILL BE ENCOUNTERING AN INCREASINGLY UNSTABLE ENVIRONMENT WHICH IS ALREADY OCCURRING OVER WESTERN ILLINOIS WITH LATEST RAP ANALYSIS SHOWING STEADILY STEEPENING LOW LEVEL LAPSE RATES. LIMITING FACTORS SUCH HIGH CIN IN PLACE WILL ERODE THROUGH MID DAY WHILE CURRENT MODERATE INSTABILITY AXIS FROM NORTHWEST ILLINOIS SOUTH TO WEST CENTRAL ILLINOIS BEGINS SPREADING EASTWARD. SHORT TERM GUIDANCE IN FAIR AGREEMENT WITH THE TIMING OF THIS OCCURRENCE AROUND THE 19Z TO 20Z TIME FRAME...AND WILL BE OCCURRING AS LARGE SCALE ASCENT WITH APPROACHING SYSTEM SPREADS EAST. MOST CURRENT GUIDANCE THIS MORNING IN AGREEMENT WITH DEVELOPING PRECIP ACROSS THE CWA THIS AFTERNOON AND ALTHOUGH I DO AGREE WITH THE IDEA/SOLUTION...I WONDER IF THE COVERAGE WILL BE AS EXTENSIVE AS IS BEING ADVERTISED. THIS CONCERN IS TIED TO LOW LEVEL CONVERGENCE POTENTIAL WITH WHICH CURRENT GUIDANCE IS APPEARING TO BE OVERDOING AT THIS TIME. IF THIS OVERESTIMATE CONTINUES...COVERAGE MAY NOT BE AS EXTENSIVE. NONETHELESS...DESPITE THIS LIMITING FACTOR FEEL THAT LARGE SCALE SUPPORT IN A MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT SHOULD BE ENOUGH TO AT LEAST DEVELOP SCATTERED DEVELOPMENT THIS AFTERNOON. CURRENT ASSESSMENT WOULD PLACE HIGHER THREAT FOR STRONG TO SEVERE WEATHER ACROSS THE WEST AND SOUTHWEST CWA WHERE BETTER INSTABILITY WILL RESIDE...BUT AS THE STABLE ENVIRONMENT ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA BECOMES MORE UNSTABLE LATER THIS AFTERNOON FEEL THAT ALL AREAS COULD POTENTIALLY HAVE THE SAME THREAT. SO DONT WANT TO REALLY POINT OUT ONE AREA OVER THE OTHER AT THIS TIME...BUT WILL CONTINUE TO MONITOR THIS POTENTIAL WITH AN UPDATED AFD WITH LATEST THINKING LIKELY BY MID DAY. AREAS ALONG AND WEST OF INTERSTATE 39 COULD OBSERVE SCATTERED STRONG TO SEVERE THUNDERSTORM DEVELOPMENT BY 19-20Z...SPREADING EAST THROUGH REMAINING AREAS IN NORTH CENTRAL ILLINOIS AND THEN NORTHEAST ILLINOIS IN THE 20-22Z TIME FRAME. CONFIDENCE IS LOWER WITH REGARD TO STRONG/SEVERE THREAT IN NORTHWEST INDIANA...BUT IF THIS WERE TO SPREAD EAST INTO THESE AREAS IT WOULD BE IN THE 22-23Z TIME WINDOW. THE MAIN SEVERE THREAT TODAY WILL BE DAMAGING WIND GUSTS...BUT HAIL COULD POSSIBLY BECOME AN ISSUE ESPECIALLY IN ANY OF THE MORE DEVELOPED THUNDERSTORMS. RODRIGUEZ && .DISCUSSION... 339 AM CDT THE BASIC PATTERN THAT HAS NOW BEEN IN PLACE FOR NEARLY A WEEK WILL CONTINUE THROUGH MONDAY...WHICH MEANS NUMEROUS FORECAST CHALLENGES ON THIS SUMMER SOLSTICE. MORNING FOG AND STRATUS IS FIRST IN THE TIMELINE FOLLOWED BY ITS IMPACT ON TEMPERATURES AND DESTABILIZATION FOR THUNDERSTORM COVERAGE THIS AFTERNOON. QUANTIFYING ANY SEVERE POTENTIAL ALSO NEEDED TO BE ASSESSED. FINALLY...CONTINUED THUNDERSTORM CHANCES...ESPECIALLY THROUGH MONDAY NIGHT...ROUNDED OUT THE FORECAST THIS MORNING. FOG AND TEMPERATURES... DENSE FOG THAT HAD EXPANDED INLAND LAST EVENING BEHIND THE IMPRESSIVE LAKE BREEZE,,,WHICH AS OF 330 AM HAS FINALLY STALLED NEAR INTERSTATE 74...CONTINUES OVER LAKE ADJACENT COUNTIES. WEB CAMS AND REPORTS INDICATE THIS IS MOST DENSE NEAR THE LAKE SHORE AND WILL CONTINUE THE DENSE FOG ADVISORY THROUGH 9 AM...WITH POTENTIALLY SOME SHORELINE LOCALES DOWN TO A FEW HUNDRED FEET VISIBILITY. VAD PROFILES INDICATE THE NORTHEAST FLOW IS ABOUT 2000-3000FT THICK AND AN AMDAR SOUNDING FROM LAST EVE INDICATES SATURATION IS ONLY ABOUT HALF OF THAT. WITH THIS BEING THE LONGEST DAYLIGHT OF THE YEAR ONE WOULD THINK WE COULD MIX THROUGH THIS QUICKLY...ESPECIALLY WITH THE SOURCE FLOW OFF THE LAKE HAVING CONSIDERABLY WEAKENED. THE ONE CONCERN WITH THAT IS CONVECTIVE DEBRIS CLOUDS ARE SPREADING OVER THIS WHICH WILL FURTHER INSULATE THIS MORNING. SO THAT WILL NEED TO BE WATCHED. HAVE ADJUSTED FORECAST HOURLY TEMPERATURES TO SLOW THE RATE OF WARMING CONSIDERABLY AND THAT LED TO COOLER HIGH TEMPERATURES. WHILE TEMPERATURES WILL COULD DEPEND ON CONVECTIVE INITIATION TIME AND COVERAGE /SEE BELOW/...FEEL THAT UNDERCUTTING GUIDANCE AND CLIMO WAS THE WAY TO GO...OWING TO THE MUCH COOLER-THAN-NORMAL WATER TEMPERATURES OF LAKE MICHIGAN WHICH FED THIS AREA OF FOG/STRATUS. THUNDERSTORM POTENTIAL... MULTIPLE LOW AMPLITUDE UPPER DISTURBANCES WILL TRANSLATE EASTWARD TODAY ACROSS A BELT OF ZONAL FLOW EXTENDING FROM THE CENTRAL PLAINS OVER THE FORECAST AREA. THIS IS ON THE NORTHERN END OF CONTINUED HIGH PRECIPITABLE WATER AND UNSTABLE AIR. ONGOING CONVECTION ACROSS WESTERN AND CENTRAL IA AS OF 330 AM HAS WEAKENED CONSIDERABLY WITH ONLY MARGINAL MOISTURE TRANSPORT FEEDING IT. DOES LOOK LIKE THE SHORT WAVE MAY BE CONVECTIVELY ENHANCED WITH A POSSIBLE MCV AND TIMING THAT FEATURE SEEMS KEY FOR OUR MAIN STORM CHANCES TODAY. THE SUITE OF GUIDANCE VARIES CONSIDERABLY AND GIVEN THAT AND SIMPLY THE TRICKY SYNOPTIC POSITION WE ARE IN...AS WELL AS THE MESOSCALE FACTOR OF THE CURRENT FOG/STRATUS...CONFIDENCE IS LOW ON THUNDERSTORM COVERAGE AND TIMING TODAY. INCREASE POPS GRADUALLY THIS MORNING WITH SOME SCATTERED ELEVATED STORMS POSSIBLE IN NORTH CENTRAL IL...AND THEN MORE SO EARLY THIS AFTERNOON AS MID-LEVEL FEATURE PASSES OVER THE FORECAST AREA. CONVECTIVE TEMPERATURES LOOK TO BE AROUND 80 DEGREES AND NOT CERTAIN IF PARTS OF NORTHEAST IL WILL REACH THAT...SO KEEP HIGHER POPS MAINLY ALONG AND SOUTH OF THE MORE STABLE LOW-LEVEL AIR IN PLACE /JUST SOUTH OF CHICAGO/. THIS ALSO IS WHERE LOW-LEVEL CONVERGENCE EXISTS...ALBEIT WITH AWFULLY WEAK FLOW. SO AM NOT ENVISIONING GREAT COVERAGE OF AFTERNOON STORMS BUT ENOUGH TO SUPPORT 40 TO 50 PERCENT POPS AND HAVE GONE WITH SCATTERED WORDING. CONVECTIVE CELLS POSSIBLY BECOMING MORE MULTICELL WITH SMALL-SCALE COLD POOLS ARE THE PROBABLE EVOLUTION. MID-LEVEL LAPSE RATES ARE POOR AND THE THERMODYNAMIC ENVIRONMENT LOOKS ALREADY HINDERED BY THE INVERSION IN PLACE...SO NOT EXPECTING MUCH FOR HAIL...BUT SOME OF THE MORE ORGANIZED STORMS COULD HAVE AN ISOLATED WIND THREAT DUE TO PRECIP LOADING AND SOME HIGHER DOWNDRAFT CAPE INDICATED BY A FEW HIGH-RES MODELS. THIS WOULD SEEM A LITTLE MORE FAVORED SOUTH OF A ROCKFORD TO RENSSELAER LINE. TONIGHT... GRADUAL WARM AIR ADVECTION AND ANOTHER ONE OR TWO MINOR IMPULSES MAY CONTINUE SEPARATE SCATTERED STORMS FROM THE EARLIER ACTIVITY AFTER DARK...NAMELY OVER THE WESTERN AND SOUTHERN FORECAST AREA. IN ADDITION...LIGHT WIND FLOW ELSEWHERE MAY ALLOW STRATUS AND/OR FOG TO DEVELOP. THIS AGAIN WOULD BE ESPECIALLY FAVORED NEAR THE LAKE SHORE. HAVE ADDED FOG MENTION ONCE AGAIN IN CHICAGO BEGINNING LATER THIS EVE. SUNDAY AND MONDAY... WARM AIR ADVECTION IS FORECAST TO INCREASE ON SUNDAY WITH THE CHANCE FOR SCATTERED STORMS. MODEL GUIDANCE IS IN GOOD AGREEMENT WITH NOTHING OVERLY ORGANIZED...SO HAVE KEPT POPS NEAR WHERE THEY WERE. TEMPERATURES AGAIN WILL BE TRICKY...REMAINING MUCH COOLER NEAR THE LAKE AND POTENTIALLY HAVING TO FIGHT THROUGH MORNING STRATUS. HEIGHT FALLS ARE EXPECTED TO SPREAD INTO THE FORECAST AREA ON MONDAY AND THAT LOOKS TO PRESENT THE BEST CHANCE FOR STORMS INCLUDING INTO MONDAY NIGHT AS THE FRONT APPROACHES AND MOVES THROUGH. PRECIPITABLE WATER IS ANTICIPATED TO CLIMB BACK TO NEAR 1.75 INCHES WITH STRONG DEEP LAYER MOISTURE CONVERGENCE. WHILE THE DEEP LAYER SHEAR IS NOT PARTICULARLY STRONG OWING TO THE MARGINAL MID-LEVEL FLOW...ENOUGH INSTABILITY AND FOCUS IS PRESENT WITH THE SYNOPTIC PATTERN TO WARRANT A HIGHER LIKELIHOOD FOR RAIN. THE MORE SUN AND GREATER INSTABILITY ON MONDAY THEN THE LIKELY BETTER CHANCES FOR SOME SEVERE POSSIBILITY. TUESDAY AND BEYOND... LONG RANGE GUIDANCE IS IN DECENT AGREEMENT WITH RAIN CHANCES DIMINISHING THROUGH TUESDAY WITH THE AIR MASS BEING SOMEWHAT SCOURED OUT SEEING DEW POINTS FORECAST DOWN INTO THE LOWER 60S. THE UPPER AND MID-LEVEL PATTERN WILL KEEP US SOMEWHAT UNSETTLED...THOUGH DEEP MOISTURE AND INSTABILITY WILL BE LESS. HAVE A LOT OF SMALL POPS BUT THE OVERALL PATTERN TUE-THU DOES NOT LOOK CONDUCIVE FOR HIGH IMPACT WEATHER. ONSHORE FLOW ON A FEW MIDWEEK DAYS LOOKS TO KEEP TEMPERATURES ONCE AGAIN QUITE A BIT COOLER NEAR THE LAKE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * TIMING OF RECOVERY FROM LIFR TO VFR AROUND 15Z. * TIMING AND DURATION OF TSRA THIS AFTERNOON. * TIMING OF CIGS/VIS DROPPING TO IFR/LIFR OVERNIGHT TONIGHT. KREIN/BEACH //DISCUSSION...UPDATED 12Z... MAIN CONCERNS REMAIN THE TIMING OF THE IMPROVEMENT OF CONDITIONS FROM LIFR TO VFR LATER THIS MORNING AND THEN THE TIMING OF TSRA TO IMPACT THE TERMINALS THIS AFTERNOON. FOR THE CIGS/VIS...EXPECT A GRADUAL IMPROVEMENT THIS MORNING. HAD INITIALLY HAD A FASTER IMPROVEMENT WITH THE GREATER SUN ANGLE FOR THE FIRST DAY OF SUMMER...BUT CIRRUS BLOWOFF FROM UPSTREAM CONVECTIVE ACTIVITY WILL SLOW THE SFC WARMING AND MIXING...SO WILL START OUT THE 12Z TAFS AT LIFR LEVELS. HAVE NOTED TOWER VISIBILITY OF 1/8SM IN THE 11Z ORD METAR...BUT ANTICIPATE GRADUAL IMPROVEMENT TO VFR BY ARND 14Z. THE OTHER CONCERN IS TIMING OF TSRA INCREASING IN COVERAGE AND HOW THE TERMINALS MAY BE IMPACTED. AT 11Z...RADAR TRENDS INDICATE DIMINISHING COVERAGE OVER IOWA...WITH A SHORT LINE OF STORMS MOVING INTO SWRN WI LIKELY ASSOCIATED WITH AN OUTFLOW BOUNDARY FROM THE EARLIER STORMS. DO NOT ANTICIPATE THAT THIS LINE WILL IMPACT RFD...BUT HAVE MOVED UP THE TIMING OF TS AT THE TERMINALS AS THE LATEST HIGH RES MODEL GUIDANCE AS WELL AS LATEST RADAR TRENDS ALL POINT TO FASTER PROGRESSION OF THE PARENT SHORTWAVE. THERE STILL REMAINS SOME QUESTION AS TO THE TIMING OF THE DEVELOPMENT...WITH THE RFD AREA POSSIBLY SEEING MORE SCT TSRA WITH COVERAGE INCREASING AS THE SYSTEM MOVES THROUGH NRN IL INTO NRN IN. THE SYSTEM SHOULD BE RATHER FAST MOVING AND DURATION OF IMPACT SHOULD BE FAIRLY SHORT...SO HAVE GONE WITH A 2 HR TEMPO GROUP. FOLLOWING THE PASSAGE OF THIS SYSTEM...CLOUD COVER SHOULD CLEAR OUT OVERNIGHT...AND WITH DECREASING WINDS AND AMPLE MOISTURE IN PLACE...THERE SHOULD BE A RETURN OF FOG AND STRATUS OVERNIGHT. HAVE CONSERVATIVELY INTRODUCED IFR/LIFR CONDITIONS AT THE END OF THE PERIOD...BUT THERE IS THE POSSIBILITY CONDITIONS...ESPECIALLY VISIBILITY COULD DROP LOWER. KREIN //ORD AND MDW CONFIDENCE...UPDATED 14Z... * LOW TO MEDIUM CONFIDENCE IN TIMING OF CONDITIONS IMPROVING TO VFR. * MEDIUM CONFIDENCE IN TIMING OF TSRA IMPACING THE TERMINALS. * MEDIUM CONFIDENCE IN WIND TRENDS. * MEDIUM CONFIDENCE IN CONDTIONS DROPPING TO IFR/LIFR AGAIN TONIGHT...BUT LOWER CONFIDENCE IN TIMING. KREIN/BEACH //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE TSRA. MONDAY...TSRA LIKELY. TUESDAY THROUGH THURSDAY...PERIOD CHANCES FOR TSRA/SHRA. THURSDAY NIGHT AND FRIDAY...VFR. WX NIL. KREIN && .MARINE... 245 AM CDT HIGH PRESSURE CENTERED WILL SIT OVER JAMES BAY THROUGH SATURDAY NIGHT WITH WEAK RIDGING EXTENDING SOUTH ACROSS LAKE MICHIGAN TO THE LOWER MISSISSIPPI VALLEY. A WEAK STATIONARY FRONT IS DRAPED FROM NORTHERN MINNESOTA...JUST SOUTH OF THE LAKE TO THE OHIO VALLEY. WITH WARM...MOIST AIR SPREADING OVER THE COLD LAKE WATER AND SHIP OBS AND COASTAL SITES AND WEB CAMS INDICATING DENSE FOG...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR ALL OF THE OPEN WATERS AND THE ILLINOIS AND INDIANA NEARSHORE WATERS. HAVE EXTENDED THE DENSE FOG ADVISORY THROUGH SUNDAY MORNING AS THERE WILL BE LITTLE CHANGE TO THE AIRMASS OVER THE LAKE. THE EXCEPTION MAY BE THE FAR NORTHERN PORTION OF THE LAKE...WHERE WINDS SHOULD TREND A LITTLE MORE EASTERLY THAN SOUTHERLY AND ADVECT SOME DRIER AIR OVER THE LAKE...LIMITING THE DENSE FOG POTENTIAL. A COMPLEX AREA OF LOW PRESSURE OVER THE CENTRAL PLAINS WITH MULTIPLE LOW PRESSURE CENTERS...WILL GRADUALLY MOVE EAST ACROSS THE PLAINS AND TO THE WESTERN GREAT LAKES REGION BY EARLY MONDAY. A WEAK COLD FRONT SHOULD PUSH ACROSS THE LAKE MONDAY OR MONDAY NIGHT...TURNING WINDS FROM GENERALLY SOUTHERLY TO MORE NORTHERLY. AS A LARGE AREA OF HIGH PRESSURE BUILDS OUT OF CANADA TO THE UPPER GREAT LAKES TUESDAY NIGHT AND WEDNESDAY...COOLER...DRIER AIR WILL OVERSPREAD THE LAKE. THE COMBINATION OF THE FRONTAL PASSAGE AND THE BUILDING HIGH PRESSURE SHOULD BRING AN END TO THE FOG POTENTIAL. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
908 AM CDT SAT JUN 21 2014 .DISCUSSION... 339 AM CDT THE BASIC PATTERN THAT HAS NOW BEEN IN PLACE FOR NEARLY A WEEK WILL CONTINUE THROUGH MONDAY...WHICH MEANS NUMEROUS FORECAST CHALLENGES ON THIS SUMMER SOLSTICE. MORNING FOG AND STRATUS IS FIRST IN THE TIMELINE FOLLOWED BY ITS IMPACT ON TEMPERATURES AND DESTABILIZATION FOR THUNDERSTORM COVERAGE THIS AFTERNOON. QUANTIFYING ANY SEVERE POTENTIAL ALSO NEEDED TO BE ASSESSED. FINALLY...CONTINUED THUNDERSTORM CHANCES...ESPECIALLY THROUGH MONDAY NIGHT...ROUNDED OUT THE FORECAST THIS MORNING. FOG AND TEMPERATURES... DENSE FOG THAT HAD EXPANDED INLAND LAST EVENING BEHIND THE IMPRESSIVE LAKE BREEZE,,,WHICH AS OF 330 AM HAS FINALLY STALLED NEAR INTERSTATE 74...CONTINUES OVER LAKE ADJACENT COUNTIES. WEB CAMS AND REPORTS INDICATE THIS IS MOST DENSE NEAR THE LAKE SHORE AND WILL CONTINUE THE DENSE FOG ADVISORY THROUGH 9 AM...WITH POTENTIALLY SOME SHORELINE LOCALES DOWN TO A FEW HUNDRED FEET VISIBILITY. VAD PROFILES INDICATE THE NORTHEAST FLOW IS ABOUT 2000-3000FT THICK AND AN AMDAR SOUNDING FROM LAST EVE INDICATES SATURATION IS ONLY ABOUT HALF OF THAT. WITH THIS BEING THE LONGEST DAYLIGHT OF THE YEAR ONE WOULD THINK WE COULD MIX THROUGH THIS QUICKLY...ESPECIALLY WITH THE SOURCE FLOW OFF THE LAKE HAVING CONSIDERABLY WEAKENED. THE ONE CONCERN WITH THAT IS CONVECTIVE DEBRIS CLOUDS ARE SPREADING OVER THIS WHICH WILL FURTHER INSULATE THIS MORNING. SO THAT WILL NEED TO BE WATCHED. HAVE ADJUSTED FORECAST HOURLY TEMPERATURES TO SLOW THE RATE OF WARMING CONSIDERABLY AND THAT LED TO COOLER HIGH TEMPERATURES. WHILE TEMPERATURES WILL COULD DEPEND ON CONVECTIVE INITIATION TIME AND COVERAGE /SEE BELOW/...FEEL THAT UNDERCUTTING GUIDANCE AND CLIMO WAS THE WAY TO GO...OWING TO THE MUCH COOLER-THAN-NORMAL WATER TEMPERATURES OF LAKE MICHIGAN WHICH FED THIS AREA OF FOG/STRATUS. THUNDERSTORM POTENTIAL... MULTIPLE LOW AMPLITUDE UPPER DISTURBANCES WILL TRANSLATE EASTWARD TODAY ACROSS A BELT OF ZONAL FLOW EXTENDING FROM THE CENTRAL PLAINS OVER THE FORECAST AREA. THIS IS ON THE NORTHERN END OF CONTINUED HIGH PRECIPITABLE WATER AND UNSTABLE AIR. ONGOING CONVECTION ACROSS WESTERN AND CENTRAL IA AS OF 330 AM HAS WEAKENED CONSIDERABLY WITH ONLY MARGINAL MOISTURE TRANSPORT FEEDING IT. DOES LOOK LIKE THE SHORT WAVE MAY BE CONVECTIVELY ENHANCED WITH A POSSIBLE MCV AND TIMING THAT FEATURE SEEMS KEY FOR OUR MAIN STORM CHANCES TODAY. THE SUITE OF GUIDANCE VARIES CONSIDERABLY AND GIVEN THAT AND SIMPLY THE TRICKY SYNOPTIC POSITION WE ARE IN...AS WELL AS THE MESOSCALE FACTOR OF THE CURRENT FOG/STRATUS...CONFIDENCE IS LOW ON THUNDERSTORM COVERAGE AND TIMING TODAY. INCREASE POPS GRADUALLY THIS MORNING WITH SOME SCATTERED ELEVATED STORMS POSSIBLE IN NORTH CENTRAL IL...AND THEN MORE SO EARLY THIS AFTERNOON AS MID-LEVEL FEATURE PASSES OVER THE FORECAST AREA. CONVECTIVE TEMPERATURES LOOK TO BE AROUND 80 DEGREES AND NOT CERTAIN IF PARTS OF NORTHEAST IL WILL REACH THAT...SO KEEP HIGHER POPS MAINLY ALONG AND SOUTH OF THE MORE STABLE LOW-LEVEL AIR IN PLACE /JUST SOUTH OF CHICAGO/. THIS ALSO IS WHERE LOW-LEVEL CONVERGENCE EXISTS...ALBEIT WITH AWFULLY WEAK FLOW. SO AM NOT ENVISIONING GREAT COVERAGE OF AFTERNOON STORMS BUT ENOUGH TO SUPPORT 40 TO 50 PERCENT POPS AND HAVE GONE WITH SCATTERED WORDING. CONVECTIVE CELLS POSSIBLY BECOMING MORE MULTICELL WITH SMALL-SCALE COLD POOLS ARE THE PROBABLE EVOLUTION. MID-LEVEL LAPSE RATES ARE POOR AND THE THERMODYNAMIC ENVIRONMENT LOOKS ALREADY HINDERED BY THE INVERSION IN PLACE...SO NOT EXPECTING MUCH FOR HAIL...BUT SOME OF THE MORE ORGANIZED STORMS COULD HAVE AN ISOLATED WIND THREAT DUE TO PRECIP LOADING AND SOME HIGHER DOWNDRAFT CAPE INDICATED BY A FEW HIGH-RES MODELS. THIS WOULD SEEM A LITTLE MORE FAVORED SOUTH OF A ROCKFORD TO RENSSELAER LINE. TONIGHT... GRADUAL WARM AIR ADVECTION AND ANOTHER ONE OR TWO MINOR IMPULSES MAY CONTINUE SEPARATE SCATTERED STORMS FROM THE EARLIER ACTIVITY AFTER DARK...NAMELY OVER THE WESTERN AND SOUTHERN FORECAST AREA. IN ADDITION...LIGHT WIND FLOW ELSEWHERE MAY ALLOW STRATUS AND/OR FOG TO DEVELOP. THIS AGAIN WOULD BE ESPECIALLY FAVORED NEAR THE LAKE SHORE. HAVE ADDED FOG MENTION ONCE AGAIN IN CHICAGO BEGINNING LATER THIS EVE. SUNDAY AND MONDAY... WARM AIR ADVECTION IS FORECAST TO INCREASE ON SUNDAY WITH THE CHANCE FOR SCATTERED STORMS. MODEL GUIDANCE IS IN GOOD AGREEMENT WITH NOTHING OVERLY ORGANIZED...SO HAVE KEPT POPS NEAR WHERE THEY WERE. TEMPERATURES AGAIN WILL BE TRICKY...REMAINING MUCH COOLER NEAR THE LAKE AND POTENTIALLY HAVING TO FIGHT THROUGH MORNING STRATUS. HEIGHT FALLS ARE EXPECTED TO SPREAD INTO THE FORECAST AREA ON MONDAY AND THAT LOOKS TO PRESENT THE BEST CHANCE FOR STORMS INCLUDING INTO MONDAY NIGHT AS THE FRONT APPROACHES AND MOVES THROUGH. PRECIPITABLE WATER IS ANTICIPATED TO CLIMB BACK TO NEAR 1.75 INCHES WITH STRONG DEEP LAYER MOISTURE CONVERGENCE. WHILE THE DEEP LAYER SHEAR IS NOT PARTICULARLY STRONG OWING TO THE MARGINAL MID-LEVEL FLOW...ENOUGH INSTABILITY AND FOCUS IS PRESENT WITH THE SYNOPTIC PATTERN TO WARRANT A HIGHER LIKELIHOOD FOR RAIN. THE MORE SUN AND GREATER INSTABILITY ON MONDAY THEN THE LIKELY BETTER CHANCES FOR SOME SEVERE POSSIBILITY. TUESDAY AND BEYOND... LONG RANGE GUIDANCE IS IN DECENT AGREEMENT WITH RAIN CHANCES DIMINISHING THROUGH TUESDAY WITH THE AIR MASS BEING SOMEWHAT SCOURED OUT SEEING DEW POINTS FORECAST DOWN INTO THE LOWER 60S. THE UPPER AND MID-LEVEL PATTERN WILL KEEP US SOMEWHAT UNSETTLED...THOUGH DEEP MOISTURE AND INSTABILITY WILL BE LESS. HAVE A LOT OF SMALL POPS BUT THE OVERALL PATTERN TUE-THU DOES NOT LOOK CONDUCIVE FOR HIGH IMPACT WEATHER. ONSHORE FLOW ON A FEW MIDWEEK DAYS LOOKS TO KEEP TEMPERATURES ONCE AGAIN QUITE A BIT COOLER NEAR THE LAKE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * TIMING OF RECOVERY FROM LIFR TO VFR AROUND 15Z. * TIMING AND DURATION OF TSRA THIS AFTERNOON. * TIMING OF CIGS/VIS DROPPING TO IFR/LIFR OVERNIGHT TONIGHT. KREIN/BEACH //DISCUSSION...UPDATED 12Z... MAIN CONCERNS REMAIN THE TIMING OF THE IMPROVEMENT OF CONDITIONS FROM LIFR TO VFR LATER THIS MORNING AND THEN THE TIMING OF TSRA TO IMPACT THE TERMINALS THIS AFTERNOON. FOR THE CIGS/VIS...EXPECT A GRADUAL IMPROVEMENT THIS MORNING. HAD INITIALLY HAD A FASTER IMPROVEMENT WITH THE GREATER SUN ANGLE FOR THE FIRST DAY OF SUMMER...BUT CIRRUS BLOWOFF FROM UPSTREAM CONVECTIVE ACTIVITY WILL SLOW THE SFC WARMING AND MIXING...SO WILL START OUT THE 12Z TAFS AT LIFR LEVELS. HAVE NOTED TOWER VISIBILITY OF 1/8SM IN THE 11Z ORD METAR...BUT ANTICIPATE GRADUAL IMPROVEMENT TO VFR BY ARND 14Z. THE OTHER CONCERN IS TIMING OF TSRA INCREASING IN COVERAGE AND HOW THE TERMINALS MAY BE IMPACTED. AT 11Z...RADAR TRENDS INDICATE DIMINISHING COVERAGE OVER IOWA...WITH A SHORT LINE OF STORMS MOVING INTO SWRN WI LIKELY ASSOCIATED WITH AN OUTFLOW BOUNDARY FROM THE EARLIER STORMS. DO NOT ANTICIPATE THAT THIS LINE WILL IMPACT RFD...BUT HAVE MOVED UP THE TIMING OF TS AT THE TERMINALS AS THE LATEST HIGH RES MODEL GUIDANCE AS WELL AS LATEST RADAR TRENDS ALL POINT TO FASTER PROGRESSION OF THE PARENT SHORTWAVE. THERE STILL REMAINS SOME QUESTION AS TO THE TIMING OF THE DEVELOPMENT...WITH THE RFD AREA POSSIBLY SEEING MORE SCT TSRA WITH COVERAGE INCREASING AS THE SYSTEM MOVES THROUGH NRN IL INTO NRN IN. THE SYSTEM SHOULD BE RATHER FAST MOVING AND DURATION OF IMPACT SHOULD BE FAIRLY SHORT...SO HAVE GONE WITH A 2 HR TEMPO GROUP. FOLLOWING THE PASSAGE OF THIS SYSTEM...CLOUD COVER SHOULD CLEAR OUT OVERNIGHT...AND WITH DECREASING WINDS AND AMPLE MOISTURE IN PLACE...THERE SHOULD BE A RETURN OF FOG AND STRATUS OVERNIGHT. HAVE CONSERVATIVELY INTRODUCED IFR/LIFR CONDITIONS AT THE END OF THE PERIOD...BUT THERE IS THE POSSIBILITY CONDITIONS...ESPECIALLY VISIBILITY COULD DROP LOWER. KREIN //ORD AND MDW CONFIDENCE...UPDATED 14Z... * LOW TO MEDIUM CONFIDENCE IN TIMING OF CONDITIONS IMPROVING TO VFR. * MEDIUM CONFIDENCE IN TIMING OF TSRA IMPACING THE TERMINALS. * MEDIUM CONFIDENCE IN WIND TRENDS. * MEDIUM CONFIDENCE IN CONDTIONS DROPPING TO IFR/LIFR AGAIN TONIGHT...BUT LOWER CONFIDENCE IN TIMING. KREIN/BEACH //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE TSRA. MONDAY...TSRA LIKELY. TUESDAY THROUGH THURSDAY...PERIOD CHANCES FOR TSRA/SHRA. THURSDAY NIGHT AND FRIDAY...VFR. WX NIL. KREIN && .MARINE... 245 AM CDT HIGH PRESSURE CENTERED WILL SIT OVER JAMES BAY THROUGH SATURDAY NIGHT WITH WEAK RIDGING EXTENDING SOUTH ACROSS LAKE MICHIGAN TO THE LOWER MISSISSIPPI VALLEY. A WEAK STATIONARY FRONT IS DRAPED FROM NORTHERN MINNESOTA...JUST SOUTH OF THE LAKE TO THE OHIO VALLEY. WITH WARM...MOIST AIR SPREADING OVER THE COLD LAKE WATER AND SHIP OBS AND COASTAL SITES AND WEB CAMS INDICATING DENSE FOG...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR ALL OF THE OPEN WATERS AND THE ILLINOIS AND INDIANA NEARSHORE WATERS. HAVE EXTENDED THE DENSE FOG ADVISORY THROUGH SUNDAY MORNING AS THERE WILL BE LITTLE CHANGE TO THE AIRMASS OVER THE LAKE. THE EXCEPTION MAY BE THE FAR NORTHERN PORTION OF THE LAKE...WHERE WINDS SHOULD TREND A LITTLE MORE EASTERLY THAN SOUTHERLY AND ADVECT SOME DRIER AIR OVER THE LAKE...LIMITING THE DENSE FOG POTENTIAL. A COMPLEX AREA OF LOW PRESSURE OVER THE CENTRAL PLAINS WITH MULTIPLE LOW PRESSURE CENTERS...WILL GRADUALLY MOVE EAST ACROSS THE PLAINS AND TO THE WESTERN GREAT LAKES REGION BY EARLY MONDAY. A WEAK COLD FRONT SHOULD PUSH ACROSS THE LAKE MONDAY OR MONDAY NIGHT...TURNING WINDS FROM GENERALLY SOUTHERLY TO MORE NORTHERLY. AS A LARGE AREA OF HIGH PRESSURE BUILDS OUT OF CANADA TO THE UPPER GREAT LAKES TUESDAY NIGHT AND WEDNESDAY...COOLER...DRIER AIR WILL OVERSPREAD THE LAKE. THE COMBINATION OF THE FRONTAL PASSAGE AND THE BUILDING HIGH PRESSURE SHOULD BRING AN END TO THE FOG POTENTIAL. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 AM SUNDAY. && $$ 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 653 AM CDT Sat Jun 21 2014 .DISCUSSION... ISSUED 248 AM CDT Sat Jun 21 2014 Surface ridging keeping control on a relatively stagnant airmass over the region. Showers, thunderstorms, and mesoscale boundaries controlling much of the dynamics for the last few days...and the trend will continue for the next few. Significant wave over NE/IA this morning progged to make its way over the Mississippi River Valley later this afternoon/evening and bring the next best chances of rain. However, some of the models weaken the impulse considerably, keeping the main wave further to the west for Sun night through Mon night. To say that the models, both high res and longer range, have been having a hard time resolving the convective elements in this hot and humid airmass is a drastic understatement. Forecast is full of pops and it is almost impossible to carve them down with much accuracy simply because it is a hot, humid, and unstable summer airmass. Scattered thunderstorms is more the rule than the exception, particularly in the afternoon (diurnal influence) and evening (evolution of convective masses that form elsewhere and propagate through.) SHORT TERM...Today and tomorrow... Hot and humid again today with weak sfc winds and heat indices into the 90s by late afternoon. GFS and NAM both relentless with the progression of the convection over NE/IA this morning, pushing into ILX this afternoon. HRRR and 4km wrf a little more familiar to recent trends and dissipates the storms as they approach the Miss River Valley and the influence of the ridge, but re-fire the outflow later in the afternoon. More recent HRRR delaying the re-fire until closer to 20z over Mid Miss River...whereas the 4km wrf igniting on several different boundaries through the afternoon. Considering the lack of consensus...will go with a combination of models, and continuity. Chances through the day, increasing this afternoon and into the evening hours. Tomorrow even less clear--scattered potential, and details potentially more accessible after the prev activity from tonight sets up any outflow boundaries. Both days in the warm and humid airmass and heat indices into the 90s. LONG TERM...Monday through Friday... Upper trof/wave pushing through the region on Monday night into Tuesday bringing signif chance, increasing from Sun night into Monday night...and a slightly cooler Tuesday through the end of the week. Still warm, but potentially less humidity as winds become more westerly on Tuesday, picking up a northerly component by Wednesday. Forecast trending drier from Tuesday through Wednesday. Another wave Thursday brings back some pops ahead of the next big storm system developing over the SW for late next weekend. HJS && .AVIATION... ISSUED 653 AM CDT Sat Jun 21 2014 Weak high pressure extending from Michigan to the SW across IL will gradually give way to a storm complex this afternoon. Strong to severe storms will be possible as instability maximizes this afternoon. Wind shear will be weak, so pulse-type storms are expected, with downburst winds the primary hazard, and hail a secondary threat. Timing and location of the storm initiation are still a bit uncertain, so VCTS was still the only inclusion in all the TAFs for the 12z issuance. PIA could see storms as early as 18z, with storms progressing east toward CMI and DEC by 20-21z. Storm chances will be primarily during a 3-4 hour window, then diminish as the complex progresses east-southeast. Diurnal stabilization should help reduce storm coverage as the evening progresses. Winds will start out light under the surface ridge axis, then increase from the south-southwest as a surface trough approaches. Wind speeds should generally remain below 10kt today, then become light and variable again this evening. Shimon && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
345 AM CDT SAT JUN 21 2014 .DISCUSSION... 339 AM CDT THE BASIC PATTERN THAT HAS NOW BEEN IN PLACE FOR NEARLY A WEEK WILL CONTINUE THROUGH MONDAY...WHICH MEANS NUMEROUS FORECAST CHALLENGES ON THIS SUMMER SOLSTICE. MORNING FOG AND STRATUS IS FIRST IN THE TIMELINE FOLLOWED BY ITS IMPACT ON TEMPERATURES AND DESTABILIZATION FOR THUNDERSTORM COVERAGE THIS AFTERNOON. QUANTIFYING ANY SEVERE POTENTIAL ALSO NEEDED TO BE ASSESSED. FINALLY...CONTINUED THUNDERSTORM CHANCES...ESPECIALLY THROUGH MONDAY NIGHT...ROUNDED OUT THE FORECAST THIS MORNING. FOG AND TEMPERATURES... DENSE FOG THAT HAD EXPANDED INLAND LAST EVENING BEHIND THE IMPRESSIVE LAKE BREEZE,,,WHICH AS OF 330 AM HAS FINALLY STALLED NEAR INTERSTATE 74...CONTINUES OVER LAKE ADJACENT COUNTIES. WEB CAMS AND REPORTS INDICATE THIS IS MOST DENSE NEAR THE LAKE SHORE AND WILL CONTINUE THE DENSE FOG ADVISORY THROUGH 9 AM...WITH POTENTIALLY SOME SHORELINE LOCALES DOWN TO A FEW HUNDRED FEET VISIBILITY. VAD PROFILES INDICATE THE NORTHEAST FLOW IS ABOUT 2000-3000FT THICK AND AN AMDAR SOUNDING FROM LAST EVE INDICATES SATURATION IS ONLY ABOUT HALF OF THAT. WITH THIS BEING THE LONGEST DAYLIGHT OF THE YEAR ONE WOULD THINK WE COULD MIX THROUGH THIS QUICKLY...ESPECIALLY WITH THE SOURCE FLOW OFF THE LAKE HAVING CONSIDERABLY WEAKENED. THE ONE CONCERN WITH THAT IS CONVECTIVE DEBRIS CLOUDS ARE SPREADING OVER THIS WHICH WILL FURTHER INSULATE THIS MORNING. SO THAT WILL NEED TO BE WATCHED. HAVE ADJUSTED FORECAST HOURLY TEMPERATURES TO SLOW THE RATE OF WARMING CONSIDERABLY AND THAT LED TO COOLER HIGH TEMPERATURES. WHILE TEMPERATURES WILL COULD DEPEND ON CONVECTIVE INITIATION TIME AND COVERAGE /SEE BELOW/...FEEL THAT UNDERCUTTING GUIDANCE AND CLIMO WAS THE WAY TO GO...OWING TO THE MUCH COOLER-THAN-NORMAL WATER TEMPERATURES OF LAKE MICHIGAN WHICH FED THIS AREA OF FOG/STRATUS. THUNDERSTORM POTENTIAL... MULTIPLE LOW AMPLITUDE UPPER DISTURBANCES WILL TRANSLATE EASTWARD TODAY ACROSS A BELT OF ZONAL FLOW EXTENDING FROM THE CENTRAL PLAINS OVER THE FORECAST AREA. THIS IS ON THE NORTHERN END OF CONTINUED HIGH PRECIPITABLE WATER AND UNSTABLE AIR. ONGOING CONVECTION ACROSS WESTERN AND CENTRAL IA AS OF 330 AM HAS WEAKENED CONSIDERABLY WITH ONLY MARGINAL MOISTURE TRANSPORT FEEDING IT. DOES LOOK LIKE THE SHORT WAVE MAY BE CONVECTIVELY ENHANCED WITH A POSSIBLE MCV AND TIMING THAT FEATURE SEEMS KEY FOR OUR MAIN STORM CHANCES TODAY. THE SUITE OF GUIDANCE VARIES CONSIDERABLY AND GIVEN THAT AND SIMPLY THE TRICKY SYNOPTIC POSITION WE ARE IN...AS WELL AS THE MESOSCALE FACTOR OF THE CURRENT FOG/STRATUS...CONFIDENCE IS LOW ON THUNDERSTORM COVERAGE AND TIMING TODAY. INCREASE POPS GRADUALLY THIS MORNING WITH SOME SCATTERED ELEVATED STORMS POSSIBLE IN NORTH CENTRAL IL...AND THEN MORE SO EARLY THIS AFTERNOON AS MID-LEVEL FEATURE PASSES OVER THE FORECAST AREA. CONVECTIVE TEMPERATURES LOOK TO BE AROUND 80 DEGREES AND NOT CERTAIN IF PARTS OF NORTHEAST IL WILL REACH THAT...SO KEEP HIGHER POPS MAINLY ALONG AND SOUTH OF THE MORE STABLE LOW-LEVEL AIR IN PLACE /JUST SOUTH OF CHICAGO/. THIS ALSO IS WHERE LOW-LEVEL CONVERGENCE EXISTS...ALBEIT WITH AWFULLY WEAK FLOW. SO AM NOT ENVISIONING GREAT COVERAGE OF AFTERNOON STORMS BUT ENOUGH TO SUPPORT 40 TO 50 PERCENT POPS AND HAVE GONE WITH SCATTERED WORDING. CONVECTIVE CELLS POSSIBLY BECOMING MORE MULTICELL WITH SMALL-SCALE COLD POOLS ARE THE PROBABLE EVOLUTION. MID-LEVEL LAPSE RATES ARE POOR AND THE THERMODYNAMIC ENVIRONMENT LOOKS ALREADY HINDERED BY THE INVERSION IN PLACE...SO NOT EXPECTING MUCH FOR HAIL...BUT SOME OF THE MORE ORGANIZED STORMS COULD HAVE AN ISOLATED WIND THREAT DUE TO PRECIP LOADING AND SOME HIGHER DOWNDRAFT CAPE INDICATED BY A FEW HIGH-RES MODELS. THIS WOULD SEEM A LITTLE MORE FAVORED SOUTH OF A ROCKFORD TO RENSSELAER LINE. TONIGHT... GRADUAL WARM AIR ADVECTION AND ANOTHER ONE OR TWO MINOR IMPULSES MAY CONTINUE SEPARATE SCATTERED STORMS FROM THE EARLIER ACTIVITY AFTER DARK...NAMELY OVER THE WESTERN AND SOUTHERN FORECAST AREA. IN ADDITION...LIGHT WIND FLOW ELSEWHERE MAY ALLOW STRATUS AND/OR FOG TO DEVELOP. THIS AGAIN WOULD BE ESPECIALLY FAVORED NEAR THE LAKE SHORE. HAVE ADDED FOG MENTION ONCE AGAIN IN CHICAGO BEGINNING LATER THIS EVE. SUNDAY AND MONDAY... WARM AIR ADVECTION IS FORECAST TO INCREASE ON SUNDAY WITH THE CHANCE FOR SCATTERED STORMS. MODEL GUIDANCE IS IN GOOD AGREEMENT WITH NOTHING OVERLY ORGANIZED...SO HAVE KEPT POPS NEAR WHERE THEY WERE. TEMPERATURES AGAIN WILL BE TRICKY...REMAINING MUCH COOLER NEAR THE LAKE AND POTENTIALLY HAVING TO FIGHT THROUGH MORNING STRATUS. HEIGHT FALLS ARE EXPECTED TO SPREAD INTO THE FORECAST AREA ON MONDAY AND THAT LOOKS TO PRESENT THE BEST CHANCE FOR STORMS INCLUDING INTO MONDAY NIGHT AS THE FRONT APPROACHES AND MOVES THROUGH. PRECIPITABLE WATER IS ANTICIPATED TO CLIMB BACK TO NEAR 1.75 INCHES WITH STRONG DEEP LAYER MOISTURE CONVERGENCE. WHILE THE DEEP LAYER SHEAR IS NOT PARTICULARLY STRONG OWING TO THE MARGINAL MID-LEVEL FLOW...ENOUGH INSTABILITY AND FOCUS IS PRESENT WITH THE SYNOPTIC PATTERN TO WARRANT A HIGHER LIKELIHOOD FOR RAIN. THE MORE SUN AND GREATER INSTABILITY ON MONDAY THEN THE LIKELY BETTER CHANCES FOR SOME SEVERE POSSIBILITY. TUESDAY AND BEYOND... LONG RANGE GUIDANCE IS IN DECENT AGREEMENT WITH RAIN CHANCES DIMINISHING THROUGH TUESDAY WITH THE AIR MASS BEING SOMEWHAT SCOURED OUT SEEING DEW POINTS FORECAST DOWN INTO THE LOWER 60S. THE UPPER AND MID-LEVEL PATTERN WILL KEEP US SOMEWHAT UNSETTLED...THOUGH DEEP MOISTURE AND INSTABILITY WILL BE LESS. HAVE A LOT OF SMALL POPS BUT THE OVERALL PATTERN TUE-THU DOES NOT LOOK CONDUCIVE FOR HIGH IMPACT WEATHER. ONSHORE FLOW ON A FEW MIDWEEK DAYS LOOKS TO KEEP TEMPERATURES ONCE AGAIN QUITE A BIT COOLER NEAR THE LAKE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LIFR/VLIFR CIGS OVERNIGHT INTO EARLY SATURDAY MORNING. * IFR VIS LIKELY OVERNIGHT INTO EARLY SATURDAY MORNING. * IMPROVEMENT TO VFR LIKELY SATURDAY MORNING...TIMING UNCERTAIN. * CHANCE TSRA SATURDAY AFTERNOON AND EARLY EVENING. KREIN //DISCUSSION...UPDATED 06Z... LAKE BREEZE FRONT THAT SWEPT THROUGH THE CHICAGO METRO TERMINALS CONTINUES TO PUSH INLAND AND IS APPROACHING RFD. BEHIND THIS BOUNDARY A DEEP MARINE LAYER IS SETTING UP WITH LOW STRATUS PUSHING WELL INLAND...WHILE THE LOWEST VISIBILITIES ARE REMAINING CLOSER TO THE LAKE. ANTICIPATE THAT RFD/DPA SHOULD KEEP VIS IN MVFR RANGES...BUT CIGS SHOULD DROP TO IFR/LIFR LEVELS. THE CHICAGO METRO TERMINALS SHOULD SEE LITTLE IMPROVEMENT UNTIL A FEW HOURS AFTER SUNRISE WHEN THE HIGH SUN ANGLE WILL ALLOW THE LOW STRATUS AND FOG TO BURN OFF. THE TIMING OF IMPROVEMENT IS STILL A LITTLE QUESTIONABLE...BUT CLIMATOLOGICALLY...14Z IS A TYPICAL BURN OFF TIME. THE NEXT CONCERN WILL BE THUNDERSTORM CHANCES SATURDAY AFTERNOON. THE LATEST HIGH RES MODEL GUIDANCE SUGGESTS THAT THE CONVECTIVE ACTIVITY CURRENTLY OVER SERN NE/SWRN IA WILL TRACK EWD OVERNIGHT. THIS ACTIVITY SHOULD WEAKEN AS IT PASSES EWD OVERNIGHT BUT SHOULD STRENGTHEN AGAIN DURG THE AFTERNOON HOURS. CURRENTLY...ANTICIPATE THAT THE REJUVENATED CONVECTIVE COMPLEX SHOULD MOVE THROUGH NRN/CNTRL IL DURG THE AFTERNOON HOURS...SO HAVE INTRODUCED A PROB30 GROUP TO THE TAFS. THERE IS SOME UNCERTAINTY AS TO THE NRN EXTEND OF THE CONVECTIVE ACTIVITY WITH SOME GUIDANCE SUGGESTING THE THE NRN EXTENT OF THE TSRA WILL BE ALONG THE I-80 CORRIDOR...REMAINING SOUTH OF THE TERMINALS...WHILE OTHER GUIDANCE SUGGESTS THAT THE TERMINALS WILL BE RIGHT IN THE TRACK OF THE THUNDER. SO...GIVEN THIS UNCERTAINTY...WILL GO WITH A PROB30 TO TREND THE TS CHANCES UPWARD AND THEN REFINE AS THE SITUATION BECOMES A BIT MORE CLEAR. KREIN //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN LIFR/VLIFR CIGS TONIGHT...LOW CONFIDENCE IN TIMING OF IMPROVEMENT TO VFR SATURDAY. * HIGH CONFIDENCE IN WINDS TONIGHT...MEDIUM CONFIDENCE IN WINDS BY SATURDAY AFTERNOON. * LOW CONFIDENCE IN TSRA TIMING AND COVERAGE SATURDAY AFTERNOON. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...CHANCE OF TSRA...OTHERWISE GENERALLY VFR. MONDAY AND MONDAY NIGHT...A PERIOD OF TSRA LIKELY. TUESDAY AND THURSDAY...GENERALLY VFR. IZZI && .MARINE... 245 AM CDT HIGH PRESSURE CENTERED WILL SIT OVER JAMES BAY THROUGH SATURDAY NIGHT WITH WEAK RIDGING EXTENDING SOUTH ACROSS LAKE MICHIGAN TO THE LOWER MISSISSIPPI VALLEY. A WEAK STATIONARY FRONT IS DRAPED FROM NORTHERN MINNESOTA...JUST SOUTH OF THE LAKE TO THE OHIO VALLEY. WITH WARM...MOIST AIR SPREADING OVER THE COLD LAKE WATER AND SHIP OBS AND COASTAL SITES AND WEB CAMS INDICATING DENSE FOG...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR ALL OF THE OPEN WATERS AND THE ILLINOIS AND INDIANA NEARSHORE WATERS. HAVE EXTENDED THE DENSE FOG ADVISORY THROUGH SUNDAY MORNING AS THERE WILL BE LITTLE CHANGE TO THE AIRMASS OVER THE LAKE. THE EXCEPTION MAY BE THE FAR NORTHERN PORTION OF THE LAKE...WHERE WINDS SHOULD TREND A LITTLE MORE EASTERLY THAN SOUTHERLY AND ADVECT SOME DRIER AIR OVER THE LAKE...LIMITING THE DENSE FOG POTENTIAL. A COMPLEX AREA OF LOW PRESSURE OVER THE CENTRAL PLAINS WITH MULTIPLE LOW PRESSURE CENTERS...WILL GRADUALLY MOVE EAST ACROSS THE PLAINS AND TO THE WESTERN GREAT LAKES REGION BY EARLY MONDAY. A WEAK COLD FRONT SHOULD PUSH ACROSS THE LAKE MONDAY OR MONDAY NIGHT...TURNING WINDS FROM GENERALLY SOUTHERLY TO MORE NORTHERLY. AS A LARGE AREA OF HIGH PRESSURE BUILDS OUT OF CANADA TO THE UPPER GREAT LAKES TUESDAY NIGHT AND WEDNESDAY...COOLER...DRIER AIR WILL OVERSPREAD THE LAKE. THE COMBINATION OF THE FRONTAL PASSAGE AND THE BUILDING HIGH PRESSURE SHOULD BRING AN END TO THE FOG POTENTIAL. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ006-ILZ014 UNTIL 9 AM SATURDAY. IN...DENSE FOG ADVISORY...INZ001-INZ002 UNTIL 9 AM SATURDAY. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 AM SUNDAY. && $$ 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 314 AM CDT Sat Jun 21 2014 .DISCUSSION... ISSUED 248 AM CDT Sat Jun 21 2014 Surface ridging keeping control on a relatively stagnant airmass over the region. Showers, thunderstorms, and mesoscale boundaries controlling much of the dynamics for the last few days...and the trend will continue for the next few. Significant wave over NE/IA this morning progged to make its way over the Mississippi River Valley later this afternoon/evening and bring the next best chances of rain. However, some of the models weaken the impulse considerably, keeping the main wave further to the west for Sun night through Mon night. To say that the models, both high res and longer range, have been having a hard time resolving the convective elements in this hot and humid airmass is a drastic understatement. Forecast is full of pops and it is almost impossible to carve them down with much accuracy simply because it is a hot, humid, and unstable summer airmass. Scattered thunderstorms is more the rule than the exception, particularly in the afternoon (diurnal influence) and evening (evolution of convective masses that form elsewhere and propagate through.) SHORT TERM...Today and tomorrow... Hot and humid again today with weak sfc winds and heat indices into the 90s by late afternoon. GFS and NAM both relentless with the progression of the convection over NE/IA this morning, pushing into ILX this afternoon. HRRR and 4km wrf a little more familiar to recent trends and dissipates the storms as they approach the Miss River Valley and the influence of the ridge, but refire the outflow later in the afternoon. More recent HRRR delaying the refire until closer to 20z over Mid Miss River...whereas the 4km wrf igniting on several different boundaries through the afternoon. Considering the lack of consensus...will go with a combination of models, and continuity. Chances through the day, increasing this afternoon and into the evening hours. Tomorrow even less clear--scattered potential, and details potentially more accessible after the prev activity from tonight sets up any outflow boundaries. Both days in the warm and humid airmass and heat indices into the 90s. LONG TERM...Monday through Friday... Upper trof/wave pushing through the region on Monday night into Tuesday bringing signif chance, increasing from Sun night into Monday night...and a slightly cooler Tuesday through the end of the week. Still warm, but potentially less humidity as winds become more westerly on Tuesday, picking up a northerly component by Wednesday. Forecast trending drier from Tuesday through Wednesday. Another wave Thursday brings back some pops ahead of the next big storm system developing over the SW for late next weekend. HJS && .AVIATION... ISSUED 1123 PM CDT Fri Jun 20 2014 Quiet/VFR aviation weather conditions expected across the central Illinois terminals through the bulk of the 06Z TAF valid time. Surface temperature/dew point spreads are pretty small at the moment, and this my combine with light winds and mostly clear skies to allow MVFR fog to develop by late tonight. However, so far, visibilities in the area as staying up for the most part. For Saturday, attention turns to the large, nearly stationary, storm complex that continues to expand over the central plains. While model agreement is far from good with the details, the remnants of this storm complex (or the arrival of the features helping to force it) may impact the area during the midday and afternoon hours. Scattered, diurnally driven, showers/storms are also possible even if the complex never makes it. However, kept mention no better than a VCTS mention at this time given the very low confidence in the convective details. Winds should generally be AOB 10 kts outside of any thunderstorms through the period. Bak && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
300 PM EDT SAT JUN 21 2014 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 322 AM EDT SAT JUN 21 2014 SLIGHTLY DRIER AIR WILL BE IN PLACE FOR THE BEGINNING OF TODAY. HOWEVER...WESTERN PORTIONS OF CENTRAL INDIANA COULD SEE SOME SCATTERED SHOWERS AND THUNDERSTORMS THIS EVENING AND TONIGHT FROM ONGOING ACTIVITY OVER NEBRASKA AND IOWA. FURTHER OUT...A FRONTAL BOUNDARY WILL BRING DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH MOST OF THE EXTENDED PERIOD. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1043 AM EDT SAT JUN 21 2014 LOW STRATUS DECK CONTINUES TO ADVANCE SOUTH TO THE NORTHEAST OF THE INDY METRO WITHIN WEAK AREA OF COLD ADVECTION. UNDER THE CLOUD DECK...TEMP RISES HAD BEEN STUNTED SO FAR WITH 14Z TEMPS IN THE UPPER 60S/LOWER 70S. FURTHER SOUTH/WEST...TEMPS HAD WARMED INTO THE MID/UPPER 70S. WHILE SOME MVFR VISIBILITIES ARE PRESENT UNDER THE STRATUS...FOG HAS GENERALLY DISPERSED AND HAVE REMOVED FROM THE FORECAST. WHILE STRATUS CONTINUES TO ADVANCE SOUTH...RECENT SATELLITE TRENDS INDICATE FRONT EDGE OF THE CLOUD DECK IS BEGINNING TO MIX OUT. THIS TREND SHOULD CONTINUE THROUGH 18Z WITH SKIES BECOMING PARTLY CLOUDY WITH VFR CU. THE CLOUDS THIS MORNING THOUGH ARE LIKELY TO IMPACT OVERALL HIGHS IN THE NORTHEAST THIS AFTERNOON AND HAVE DROPPED TEMPS A FEW DEGREES. FOCUS THEN SHIFTS TO CONVECTIVE POTENTIAL BEGINNING LATE AFTERNOON INTO THE EVENING HOURS. WELL DEFINED MCV LOCATED OVER EASTERN IOWA FROM THE REMNANTS OF THE OVERNIGHT CONVECTION ACROSS NEBRASKA/ IOWA. THIS FEATURE PROGGED TO TRACK EAST INTO NORTHERN ILLINOIS THROUGH THE AFTERNOON SPARKING NEW CONVECTIVE DEVELOPMENT. MAJORITY OF THE MOST CURRENT MODEL DATA BRINGING CONVECTION INTO THE NORTHERN WABASH VALLEY BY EARLY EVENING WITH STORMS CONTINUING INTO THE OVERNIGHT. STILL A LOT OF UNCERTAINTY WITH RESPECT TO HOW FAR SOUTH AND EAST THE CONVECTION CAN SPREAD ACROSS THE FORECAST AREA BEFORE DYING OUT AS AIRMASS WILL REMAIN MORE STABLE THE FURTHER EAST ONE GOES. SHORT RANGE MODEL GUIDANCE FOCUSES BETTER INSTABILITY AND DEEPER MOISTURE IN THE VICINITY OF THE RETURNING FRONTAL BOUNDARY ACROSS ILLINOIS THROUGH THIS EVENING...POSSIBLY WORKING INTO THE WESTERN PART OF THE STATE AS WELL. RAP INDICATING A SUBTLE INCREASE IN LOW LEVEL FLOW THIS EVENING WHICH WOULD SUPPORT MAINTENANCE OF SCATTERED CONVECTION INTO THE OVERNIGHT. DESPITE SPC BACKING OFF ON THE DAY 1 SLIGHT RISK TO JUST WEST OF THE AREA...HAVE MAINTAINED AN ISOLATED SEVERE MENTION IN THE HWO WITH THE BEST POTENTIAL OVER THE NORTHWEST FORECAST AREA. LOW CONFIDENCE IN AVAILABLE FORCING AND INSTABILITY ARE MITIGATING FACTORS IN SEVERE POTENTIAL FURTHER EAST ACROSS CENTRAL INDIANA. ZONE AND GRID UPDATES OUT. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 322 AM EDT SAT JUN 21 2014 THE MAIN FOCUS OF THE SHORT TERM WILL BE SHOWER/THUNDERSTORM POTENTIAL OVER WESTERN PORTIONS OF FORECAST AREA THIS EVENING AND TONIGHT. AGAIN...DETAILS ARE UNCLEAR AT THIS TIME AS TO HOW WAVES FROM CURRENT CONVECTIVE ACTIVITY OVER THE MID MISSOURI VALLEY ARE GOING TO PLAY OUT AND WILL HAVE TO BE MONITORED THROUGHOUT THE DAY. CONFIDENCE BECOMES A BIT HIGHER LATER IN THE SHORT TERM PERIOD THOUGH AS SURFACE FRONTAL BOUNDARY SHIFTS BACK TO THE NORTH ON SUNDAY AND MONDAY IN THE FORM OF A WARM FRONT. THIS WILL PROVIDE A MOIST WARM UNSTABLE ENVIRONMENT AGAIN AND FORCING FOR ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT. TEMPS...HIGHS IN THE MID TO UPPER 80S AND LOWS IN THE 70S WILL PREVAIL FOR DURATION OF SHORT TERM PERIOD...STUCK CLOSE TO A MODEL BLEND. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ISSUED AT 258 PM EDT SAT JUN 21 2014 THE MAIN FOCUS OF THE EXTENDED TIMEFRAME REMAINS ON RAINFALL CHANCES ACROSS THE AREA. THE PERIOD BEGINS WITH BROAD LOW AMPLITUDE TROUGHING OVER THE GREAT LAKES AND NORTHERN PLAINS...WITH THE FORECAST AREA UNDER WEAK ZONAL FLOW ALOFT AND POST A WEAK FRONTAL PASSAGE. DESPITE THE WIND SHIFT...THE WARM AND MOIST CONDITIONS WILL CONTINUE WITH DEWPOINTS FORECAST IN THE MIDDLE TO UPPER 60 DEGREE RANGE. A COUPLE WEAK UPPER WAVES WILL MOVE ACROSS THE AREA BY FRIDAY NIGHT...BEFORE UPPER RIDGING AMPLIFIES ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEYS FOR THE WEEKEND. STUCK CLOSE TO REGIONAL INITIALIZATION FOR POPS...KEEPING SLIGHT TO MAINLY LOW CHANCE POP IN THE FORECAST THROUGH THE EXTENDED TIMEFRAME. THE HIGHEST POPS ARRIVE ON FRIDAY AS THE RELATIVELY STRONGER OF THE SERIES OF WEAK UPPER WAVES MOVE ACROSS THE AREA. GENERALLY LOW TO MIDDLE 80S ARE EXPECTED...WITH TEMPS INCREASING TO THE MIDDLE TO UPPER 80S ON SATURDAY AS UPPER RIDGING INCREASES. && .AVIATION /DISCUSSION FOR 211800Z TAF ISSUANCE/... ISSUED AT 1253 PM EDT SAT JUN 21 2014 VFR THROUGH THE AFTERNOON AND EVENING HOURS WITH WINDS REMAINING AOB 7 KTS. COULD SEE SOME MVFR FOG DEVELOP DURING THE OVERNIGHT ESPECIALLY AT KLAF AND KBMG BASED ON MOS...SOUNDINGS AND SIMILAR CONDITIONS TO THIS MORNING. ALSO SOME POTENTIAL FOR CONVECTION TONIGHT BUT RIGHT NOW LOOKS LIKE THE PROBABILITY IS LOW ENOUGH TO LEAVE OUT OF ALL SITES BUT KLAF. AT KLAF CHANCE LOOKS HIGH ENOUGH TO INCLUDE VCTS FROM 2-9Z AND PUT THE FOG IN AFTER THAT. AT KHUF AND KIND CURRENTLY LEAVING VFR THROUGH THE PERIOD AS CONFIDENCE ON ANY RESTRICTIONS IS TOO LOW TO INCLUDE. WINDS WILL BECOME SOUTHWESTERLY AROUND 5-10 KTS BY MIDMORNING SUNDAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...RYAN SHORT TERM...TDUD LONG TERM....MRD AVIATION...CP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1254 PM EDT SAT JUN 21 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 322 AM EDT SAT JUN 21 2014 SLIGHTLY DRIER AIR WILL BE IN PLACE FOR THE BEGINNING OF TODAY. HOWEVER...WESTERN PORTIONS OF CENTRAL INDIANA COULD SEE SOME SCATTERED SHOWERS AND THUNDERSTORMS THIS EVENING AND TONIGHT FROM ONGOING ACTIVITY OVER NEBRASKA AND IOWA. FURTHER OUT...A FRONTAL BOUNDARY WILL BRING DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH MOST OF THE EXTENDED PERIOD. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1043 AM EDT SAT JUN 21 2014 LOW STRATUS DECK CONTINUES TO ADVANCE SOUTH TO THE NORTHEAST OF THE INDY METRO WITHIN WEAK AREA OF COLD ADVECTION. UNDER THE CLOUD DECK...TEMP RISES HAD BEEN STUNTED SO FAR WITH 14Z TEMPS IN THE UPPER 60S/LOWER 70S. FURTHER SOUTH/WEST...TEMPS HAD WARMED INTO THE MID/UPPER 70S. WHILE SOME MVFR VISIBILITIES ARE PRESENT UNDER THE STRATUS...FOG HAS GENERALLY DISPERSED AND HAVE REMOVED FROM THE FORECAST. WHILE STRATUS CONTINUES TO ADVANCE SOUTH...RECENT SATELLITE TRENDS INDICATE FRONT EDGE OF THE CLOUD DECK IS BEGINNING TO MIX OUT. THIS TREND SHOULD CONTINUE THROUGH 18Z WITH SKIES BECOMING PARTLY CLOUDY WITH VFR CU. THE CLOUDS THIS MORNING THOUGH ARE LIKELY TO IMPACT OVERALL HIGHS IN THE NORTHEAST THIS AFTERNOON AND HAVE DROPPED TEMPS A FEW DEGREES. FOCUS THEN SHIFTS TO CONVECTIVE POTENTIAL BEGINNING LATE AFTERNOON INTO THE EVENING HOURS. WELL DEFINED MCV LOCATED OVER EASTERN IOWA FROM THE REMNANTS OF THE OVERNIGHT CONVECTION ACROSS NEBRASKA/ IOWA. THIS FEATURE PROGGED TO TRACK EAST INTO NORTHERN ILLINOIS THROUGH THE AFTERNOON SPARKING NEW CONVECTIVE DEVELOPMENT. MAJORITY OF THE MOST CURRENT MODEL DATA BRINGING CONVECTION INTO THE NORTHERN WABASH VALLEY BY EARLY EVENING WITH STORMS CONTINUING INTO THE OVERNIGHT. STILL A LOT OF UNCERTAINTY WITH RESPECT TO HOW FAR SOUTH AND EAST THE CONVECTION CAN SPREAD ACROSS THE FORECAST AREA BEFORE DYING OUT AS AIRMASS WILL REMAIN MORE STABLE THE FURTHER EAST ONE GOES. SHORT RANGE MODEL GUIDANCE FOCUSES BETTER INSTABILITY AND DEEPER MOISTURE IN THE VICINITY OF THE RETURNING FRONTAL BOUNDARY ACROSS ILLINOIS THROUGH THIS EVENING...POSSIBLY WORKING INTO THE WESTERN PART OF THE STATE AS WELL. RAP INDICATING A SUBTLE INCREASE IN LOW LEVEL FLOW THIS EVENING WHICH WOULD SUPPORT MAINTENANCE OF SCATTERED CONVECTION INTO THE OVERNIGHT. DESPITE SPC BACKING OFF ON THE DAY 1 SLIGHT RISK TO JUST WEST OF THE AREA...HAVE MAINTAINED AN ISOLATED SEVERE MENTION IN THE HWO WITH THE BEST POTENTIAL OVER THE NORTHWEST FORECAST AREA. LOW CONFIDENCE IN AVAILABLE FORCING AND INSTABILITY ARE MITIGATING FACTORS IN SEVERE POTENTIAL FURTHER EAST ACROSS CENTRAL INDIANA. ZONE AND GRID UPDATES OUT. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 322 AM EDT SAT JUN 21 2014 THE MAIN FOCUS OF THE SHORT TERM WILL BE SHOWER/THUNDERSTORM POTENTIAL OVER WESTERN PORTIONS OF FORECAST AREA THIS EVENING AND TONIGHT. AGAIN...DETAILS ARE UNCLEAR AT THIS TIME AS TO HOW WAVES FROM CURRENT CONVECTIVE ACTIVITY OVER THE MID MISSOURI VALLEY ARE GOING TO PLAY OUT AND WILL HAVE TO BE MONITORED THROUGHOUT THE DAY. CONFIDENCE BECOMES A BIT HIGHER LATER IN THE SHORT TERM PERIOD THOUGH AS SURFACE FRONTAL BOUNDARY SHIFTS BACK TO THE NORTH ON SUNDAY AND MONDAY IN THE FORM OF A WARM FRONT. THIS WILL PROVIDE A MOIST WARM UNSTABLE ENVIRONMENT AGAIN AND FORCING FOR ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT. TEMPS...HIGHS IN THE MID TO UPPER 80S AND LOWS IN THE 70S WILL PREVAIL FOR DURATION OF SHORT TERM PERIOD...STUCK CLOSE TO A MODEL BLEND. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 234 AM EDT SAT JUN 21 2014 THE DETERMINISTIC EXTENDED MODELS ARE CONTINUING TO HAVE TIMING AND RUN TO RUN DIFFERENCES OVER THE EVOLUTION OF GREAT LAKES TROUGHING NEXT WEEK. SO...WILL ACCEPT THE REGIONAL ALLBLEND WHICH HAS CHANCE POPS EACH PERIOD THROUGH FRIDAY ASSOCIATED WITH WAVES AROUND THE BASE OF THE AFOREMENTIONED TROUGH COUPLED WITH A WARM...MOIST AND UNSTABLE ENVIRONMENT. ALLBLEND CONTINUES TO ADVERTISE THE HIGHEST POPS ON TUESDAY AS A WEAK COLD FRONT DROPS SOUTHEAST OVER THE AREA BEFORE STALLING. A LOT WILL DEPEND ON WHERE THIS FRONT ENDS UP LAYING OUT WHICH IS NEVER AN EASY CALL THIS TIME OF YEAR. SEASONABLE ALLBLEND HIGHS IN THE 80S LOOK OK FOR TEMPERATURES...AND WITH MODEL ISSUES...DO NOT WANT TO MESS MUCH WITH THEM. && .AVIATION /DISCUSSION FOR 211800Z TAF ISSUANCE/... ISSUED AT 1253 PM EDT SAT JUN 21 2014 VFR THROUGH THE AFTERNOON AND EVENING HOURS WITH WINDS REMAINING AOB 7 KTS. COULD SEE SOME MVFR FOG DEVELOP DURING THE OVERNIGHT ESPECIALLY AT KLAF AND KBMG BASED ON MOS...SOUNDINGS AND SIMILAR CONDITIONS TO THIS MORNING. ALSO SOME POTENTIAL FOR CONVECTION TONIGHT BUT RIGHT NOW LOOKS LIKE THE PROBABILITY IS LOW ENOUGH TO LEAVE OUT OF ALL SITES BUT KLAF. AT KLAF CHANCE LOOKS HIGH ENOUGH TO INCLUDE VCTS FROM 2-9Z AND PUT THE FOG IN AFTER THAT. AT KHUF AND KIND CURRENTLY LEAVING VFR THROUGH THE PERIOD AS CONFIDENCE ON ANY RESTRICTIONS IS TOO LOW TO INCLUDE. WINDS WILL BECOME SOUTHWESTERLY AROUND 5-10 KTS BY MIDMORNING SUNDAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...RYAN SHORT TERM...TDUD LONG TERM...MK AVIATION...CP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1043 AM EDT SAT JUN 21 2014 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 322 AM EDT SAT JUN 21 2014 SLIGHTLY DRIER AIR WILL BE IN PLACE FOR THE BEGINNING OF TODAY. HOWEVER...WESTERN PORTIONS OF CENTRAL INDIANA COULD SEE SOME SCATTERED SHOWERS AND THUNDERSTORMS THIS EVENING AND TONIGHT FROM ONGOING ACTIVITY OVER NEBRASKA AND IOWA. FURTHER OUT...A FRONTAL BOUNDARY WILL BRING DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH MOST OF THE EXTENDED PERIOD. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1043 AM EDT SAT JUN 21 2014 LOW STRATUS DECK CONTINUES TO ADVANCE SOUTH TO THE NORTHEAST OF THE INDY METRO WITHIN WEAK AREA OF COLD ADVECTION. UNDER THE CLOUD DECK...TEMP RISES HAD BEEN STUNTED SO FAR WITH 14Z TEMPS IN THE UPPER 60S/LOWER 70S. FURTHER SOUTH/WEST...TEMPS HAD WARMED INTO THE MID/UPPER 70S. WHILE SOME MVFR VISIBILITIES ARE PRESENT UNDER THE STRATUS...FOG HAS GENERALLY DISPERSED AND HAVE REMOVED FROM THE FORECAST. WHILE STRATUS CONTINUES TO ADVANCE SOUTH...RECENT SATELLITE TRENDS INDICATE FRONT EDGE OF THE CLOUD DECK IS BEGINNING TO MIX OUT. THIS TREND SHOULD CONTINUE THROUGH 18Z WITH SKIES BECOMING PARTLY CLOUDY WITH VFR CU. THE CLOUDS THIS MORNING THOUGH ARE LIKELY TO IMPACT OVERALL HIGHS IN THE NORTHEAST THIS AFTERNOON AND HAVE DROPPED TEMPS A FEW DEGREES. FOCUS THEN SHIFTS TO CONVECTIVE POTENTIAL BEGINNING LATE AFTERNOON INTO THE EVENING HOURS. WELL DEFINED MCV LOCATED OVER EASTERN IOWA FROM THE REMNANTS OF THE OVERNIGHT CONVECTION ACROSS NEBRASKA/ IOWA. THIS FEATURE PROGGED TO TRACK EAST INTO NORTHERN ILLINOIS THROUGH THE AFTERNOON SPARKING NEW CONVECTIVE DEVELOPMENT. MAJORITY OF THE MOST CURRENT MODEL DATA BRINGING CONVECTION INTO THE NORTHERN WABASH VALLEY BY EARLY EVENING WITH STORMS CONTINUING INTO THE OVERNIGHT. STILL A LOT OF UNCERTAINTY WITH RESPECT TO HOW FAR SOUTH AND EAST THE CONVECTION CAN SPREAD ACROSS THE FORECAST AREA BEFORE DYING OUT AS AIRMASS WILL REMAIN MORE STABLE THE FURTHER EAST ONE GOES. SHORT RANGE MODEL GUIDANCE FOCUSES BETTER INSTABILITY AND DEEPER MOISTURE IN THE VICINITY OF THE RETURNING FRONTAL BOUNDARY ACROSS ILLINOIS THROUGH THIS EVENING...POSSIBLY WORKING INTO THE WESTERN PART OF THE STATE AS WELL. RAP INDICATING A SUBTLE INCREASE IN LOW LEVEL FLOW THIS EVENING WHICH WOULD SUPPORT MAINTENANCE OF SCATTERED CONVECTION INTO THE OVERNIGHT. DESPITE SPC BACKING OFF ON THE DAY 1 SLIGHT RISK TO JUST WEST OF THE AREA...HAVE MAINTAINED AN ISOLATED SEVERE MENTION IN THE HWO WITH THE BEST POTENTIAL OVER THE NORTHWEST FORECAST AREA. LOW CONFIDENCE IN AVAILABLE FORCING AND INSTABILITY ARE MITIGATING FACTORS IN SEVERE POTENTIAL FURTHER EAST ACROSS CENTRAL INDIANA. ZONE AND GRID UPDATES OUT. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 322 AM EDT SAT JUN 21 2014 THE MAIN FOCUS OF THE SHORT TERM WILL BE SHOWER/THUNDERSTORM POTENTIAL OVER WESTERN PORTIONS OF FORECAST AREA THIS EVENING AND TONIGHT. AGAIN...DETAILS ARE UNCLEAR AT THIS TIME AS TO HOW WAVES FROM CURRENT CONVECTIVE ACTIVITY OVER THE MID MISSOURI VALLEY ARE GOING TO PLAY OUT AND WILL HAVE TO BE MONITORED THROUGHOUT THE DAY. CONFIDENCE BECOMES A BIT HIGHER LATER IN THE SHORT TERM PERIOD THOUGH AS SURFACE FRONTAL BOUNDARY SHIFTS BACK TO THE NORTH ON SUNDAY AND MONDAY IN THE FORM OF A WARM FRONT. THIS WILL PROVIDE A MOIST WARM UNSTABLE ENVIRONMENT AGAIN AND FORCING FOR ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT. TEMPS...HIGHS IN THE MID TO UPPER 80S AND LOWS IN THE 70S WILL PREVAIL FOR DURATION OF SHORT TERM PERIOD...STUCK CLOSE TO A MODEL BLEND. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 234 AM EDT SAT JUN 21 2014 THE DETERMINISTIC EXTENDED MODELS ARE CONTINUING TO HAVE TIMING AND RUN TO RUN DIFFERENCES OVER THE EVOLUTION OF GREAT LAKES TROUGHING NEXT WEEK. SO...WILL ACCEPT THE REGIONAL ALLBLEND WHICH HAS CHANCE POPS EACH PERIOD THROUGH FRIDAY ASSOCIATED WITH WAVES AROUND THE BASE OF THE AFOREMENTIONED TROUGH COUPLED WITH A WARM...MOIST AND UNSTABLE ENVIRONMENT. ALLBLEND CONTINUES TO ADVERTISE THE HIGHEST POPS ON TUESDAY AS A WEAK COLD FRONT DROPS SOUTHEAST OVER THE AREA BEFORE STALLING. A LOT WILL DEPEND ON WHERE THIS FRONT ENDS UP LAYING OUT WHICH IS NEVER AN EASY CALL THIS TIME OF YEAR. SEASONABLE ALLBLEND HIGHS IN THE 80S LOOK OK FOR TEMPERATURES...AND WITH MODEL ISSUES...DO NOT WANT TO MESS MUCH WITH THEM. && .AVIATION /DISCUSSION FOR THE 211500Z TAF ISSUANCE/... ISSUED AT 1020 AM EDT SAT JUN 21 2014 SATELLITE LOOP SHOWS A STRATUS DECK OVER NORTHERN INDIANA MAKING IT/S WAY TO THE SOUTH AND HAS REACHED KLAF. THINK IT COULD CONTINUE THERE FOR THE NEXT 2 HOURS BEFORE MIXING UP SO ADDED A TEMPO IFR GROUP FOR THIS. AT KIND ADDED A FEW015 GROUP STARTING AT 16Z SINCE THE DECK IS MOVING TOWARD THERE BUT ALSO LOOKS LIKE IT/S BREAKING UP AND PROBABLY WILL NOT IMPACT THE CEILING AND CATEGORY. PREVIOUS DISCUSSION FOLLOWS... FRONTAL BOUNDARY SHOULD BE NEAR THE TERMINALS TODAY...BUT WITH MOISTURE MARGINAL IN THE LOWER LEVELS...DIURNAL CU PROGS SUGGEST ONLY SCATTERED DIURNAL CU DESPITE CONVECTIVE TEMPERATURES WELL WITHIN REACH BY LATE MORNING. SO...CONFIDENCE IS NOT HIGH ENOUGH TO MENTION THUNDERSTORMS AT THIS TIME. HOWEVER...LAF WOULD SEEM TO HAVE THE HIGHEST CHANCE AND AFTER 00Z TONIGHT. WITH WEAK SURFACE PRESSURE GRADIENT...WINDS WILL BE LIGHT AND VARIABLE OR CALM THROUGH TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...TDUD NEAR TERM...RYAN SHORT TERM...TDUD LONG TERM...MK AVIATION...MK/CP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
523 PM MDT SUN JUN 22 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 1230 PM MDT SUN JUN 22 2014 THUNDERSTORM ACTIVITY EXPECTED TO RAMP UP QUICKLY AFTER 3 PM MDT (4 PM CDT) AS A WEATHER DISTURBANCE IGNITES A FEW STORMS IN FAR EASTERN COLORADO. AS THE DISTURBANCE MOVES EAST A LINE OF STRONG TO SEVERE THUNDERSTORMS IS EXPECTED PRODUCING LARGE HAIL...DAMAGING WINDS AND LOCALLY HEAVY RAINFALL. THE HRRR HAS BEEN SLOWLY INCREASING THE WIND GUST POTENTIAL WITH THE LINE AND WE COULD EXPERIENCE ANOTHER EPISODE OF 70+ MPH GUSTS. LOWS TONIGHT IN THE MID 50S WEST...MID 60S EAST. ON MONDAY MAY SEE SHOWERS AND THUNDERSTORMS IN THE LATE AFTERNOON HOURS...PRIMARILY ACROSS FAR EASTERN COLORADO. OTHERWISE EXPECT SOME CLOUDINESS WITH HIGHS IN THE MID 70S TO LOW 80S. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 1242 PM MDT SUN JUN 22 2014 A FEW STORMS IN SOUTHEAST COLORADO MONDAY EVENING MAY SNEAK INTO SOUTHWESTERN PARTS OF THE AREA...BUT BETTER CHANCES WILL BE AFTER MIDNIGHT AS LLJ STRENGTHENS AND SHORTWAVE TROUGH COMES OUT OF THE NORTHERN ROCKIES. STORMS MAY BE SLIGHTLY ELEVATED OVERNIGHT...WITH PARCELS ORIGINATING AROUND 800MB HAVING UP TO 1000 J/KG OF ELEVATED CAPE AND LITTLE TO NO CIN. LARGE HAIL WILL BE POSSIBLE OVERNIGHT WITH THESE STORMS. SOME OF THIS ACTIVITY WILL LINGER INTO TUESDAY MORNING...PARTICULARLY IN SOUTHWEST NEBRASKA...BEFORE AFTERNOON CONVECTION GETS GOING IN NORTHEAST COLORADO WITH THE NEXT SHORTWAVE. MODERATE INSTABILITY COMBINED WITH DEEP LAYER SHEAR OF 30-40KTS SUGGEST ANOTHER ROUND OF SEVERE STORMS AS THEY SLIDE ACROSS THE AREA TUESDAY EVENING. SOUTHEASTERLY SURFACE WINDS CONTINUE ON WEDNESDAY WITH A CORRIDOR OF VERY UNSTABLE CONDITIONS FORECAST BY THE AFTERNOON IN THE WESTERN HALF OF THE FORECAST AREA. DEEP LAYER SHEAR HOWEVER IS SOMEWHAT WEAKER AT AROUND 30KTS...BUT SHOULD BE ADEQUATE FOR SEVERE STORMS AS NEXT SHORTWAVE COMES OUT OF NORTHERN COLORADO IN THE AFTERNOON/EVENING. A SUBTLE PATTERN CHANGE OCCURS IN THE LAST HALF OF THE LONG TERM PERIOD WITH LONGWAVE TROUGH SETTLING INTO THE NORTHERN ROCKIES. THE UPPER FLOW OVER THE CENTRAL PLAINS WILL BECOME SOUTHWEST. SHORTWAVE TROUGHS ROTATING AROUND THE ROCKIES TROUGH OR EVEN THE RIDGE OVER THE CENTRAL GULF WILL PROVIDE ENOUGH LIFT TO CONTINUE THE MENTION OF DAILY THUNDERSTORM CHANCES. TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE LONG TERM. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 523 PM MDT SUN JUN 22 2014 THUNDERSTORM ACTIVITY ALREADY SPREADING WITHIN THE VICINITY OF KGLD AND THIS SHOULD OVERSPREAD THE TERMINAL AROUND 00Z. ACTIVITY MAY NOT REACH KMCK UNTIL AROUND 03Z...SO I DELAYED MENTION FOR THAT TAF. STRONGER STORMS WILL BE CAPABLE OF PRODUCING BRIEF IFR VIS AND WINDS IN EXCESS OF 50KT. HAVE KEPT TEMPO 3S-4SM GROUPS WITH NO MENTION OF HAIL OR WINDS STRONGER THAN 50KT...THOUGH THESE CONDITIONS CANT BE RULED OUT. SHORT RANGE GUIDANCE WHICH GENERALLY MATCHES CURRENT RADAR TRENDS SHOWS THIS ACTIVITY TRANSITIONING EASTWARD BY 06Z..THOUGH IT COULD LINGER LONGER AT KMCK. ADDITIONAL THUNDERSTORMS WILL POSSIBLE DEVELOP OVER EASTERN COLORADO MONDAY AFTERNOON...HOWEVER COVERAGE AT EITHER TERMINAL IS STILL IN QUESTION AS THIS SYSTEM DOES NOT APPEAR TO BE AS WELL ORGANIZED AS THE CURRENT UPPER LEVEL SYSTEM WE ARE DEALING WITH. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...99 LONG TERM...024 AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
315 PM CDT Sat Jun 21 2014 .SHORT TERM...(This Evening through Sunday) Issued at 315 PM CDT SAT JUN 21 2014 19Z water vapor imagery continues to shows a quasi-zonal flow across the central Rockies and into the plains. There may be one or two Mesoscale Convective Vortices (MCV) moving along the KS/NEB state line with the more obvious one crossing the MO river and headed into central MO. There also appears to be a subtle shortwave moving through ID and northern UT. At the surface, a trough of low pressure extended from the Dakotas south through eastern CO. Surface OBS show the better low level moisture has shifted a little to the east with much of the 70 degree dewpoints. Late this afternoon and this evening is anticipated to be mostly dry with general subsidence from the MCV over eastern KS and the deeper moisture to the east of the area. This combined with a lack of organized low level convergence should favor any isolated storms remaining east of the forecast area. Will have to watch and see if any of the convection off the higher terrain holds together long enough to reach north central KS. There are some indications from the RAP and HRRR that there could be some precip move into Republic and Cloud counties around midnight. However those solutions seem to be a little to aggressive in developing convection earlier in the day, so I don`t know how much weight to give these solutions. Will have some small POPs after midnight for far northern counties in case some shower and thunderstorm activity is able to hang together. Lows tonight should once again be mild with readings around 70 due to southerly winds and warm air remaining over the area. For Sunday, the subtle shortwave out west is progged to be moving out into the plains, mainly to the north of the forecast area. However the synoptic scale surface trough is expected to be a little further east into KS. Convergence along this boundary coupled with some weak forcing from the upper wave could cause a broken line of storms to form by the afternoon hours. Instability is expected to be high once again with good low level moisture still in place. However due to weak mid level flow, deep layer shear is progged to only be from 15 to 25 kts. This would favor multi cell clusters with a hail and strong wind hazard. North central KS looks like the most likely place for this storms to form during the afternoon. Temps for Sunday are expected to be similar to today`s or maybe a degree or two cooler. Models show a slight cooling trend at 850 and there could be higher clouds increasing by the afternoon from the potential convection to the west. Because of this have highs generally in the lower 90s. .LONG TERM...(Sunday Night through Saturday) Issued at 315 PM CDT SAT JUN 21 2014 Overall trend is for the upper wave to be less intense as it passes through Sunday night into early Monday. Still looks like a good opportunity for for most locations to receive at least one round of precip with the slow moving system weak front moving through a moist early-summer airmass and limited inhibition. Severe weather concerns should diminish with time in the evening hours with a least some chance for pockets of heavier precipitation, though setup does not point to any particularly area at this point. Monday should slowly dry with the departing wave with Monday night and much of Tuesday still looking to be the more likely dry periods of this forecast. Models do show some similarities with a weak wave passing mainly south of the area late Tuesday into Wednesday, but moisture does return north with this wave with modest flow keeping mid levels from warming too fast for at least small thunderstorm chances. Upper flow amplifies over the western and eventually central CONUS into the end of the forecast. Expect capping to increase enough for a mainly dry end to the work week with chances picking up again by Saturday as forcing increases. Temps should slowly warm through the latter portions of the week, with 90s possible by Saturday. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1142 AM CDT SAT JUN 21 2014 Chances for TS to impact the terminals appears to be relatively low due to no feature to focus convection. Therefore have kept a VFR forecast through the period. For more detail, see the update section above. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...65 AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1110 AM MDT SAT JUN 21 2014 .UPDATE... ISSUED AT 900 AM MDT SAT JUN 21 2014 UPDATE REQUIRED FOR THE REST OF THE DAY TO BETTER REPRESENT CURRENT RADAR TRENDS AND THE NEXT 8-9 HOURS OF TEMPS/DP/WINDS/POP AND WX. SHOWERS AND THUNDERSTORMS THAT HAVE BEEN LOCATED ALONG THE KS/NE BORDER THIS MORNING SLOWLY STARTING TO LOSE INTENSITY AND AREAL COVERAGE AND THIS TREND SHOULD CONTINUE THE REST OF THE MORNING. DURING THE AFTERNOON CURRENTLY EXPECTING A SFC TROUGH TO SET UP NEAR/JUST EAST OF THE CO/KS BORDER. MAY HAVE A FEW STORMS DEVELOP ALONG THIS BY MID/LATE AFTERNOON WITH A SLOW EASTWARD PUSH TO THE EAST AS A STRONG WEATHER DISTURBANCE AND BETTER UPPER JET DIVERGENCE MOVES IN TO EASTERN COLORADO. THIS SHOULD BE ENOUGH TO CREATE SOME STRONG/SEVERE STORMS IN EASTERN COLORADO AND ALONG THE SFC TROUGH IN WESTERN KANSAS/SOUTHWEST NEBRASKA. LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY THREATS. HIGH TEMPERATURES GENERALLY IN THE UPPER 80S TO LOW 90S IN EASTERN COLORADO WITH LOW TO MID 90S EAST OF THE BORDER. MAY SEE SOME UPPER 90S...ESPECIALLY ACROSS THE EAST THROUGH SOUTH WHERE IMPACTS OF APPROACHING CIRRUS FROM THE WEST MAY BE LESS. && .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 246 AM MDT SAT JUN 21 2014 A RIDGE OVER THE PLAINS WILL FLATTEN SOME TONIGHT. FLOW WILL BECOME ZONAL ON SUNDAY AND THEN TURN NORTHWEST MONDAY/MONDAY NIGHT. A SURFACE TROUGH WILL BE NEAR NORTHEAST COLORADO TODAY THROUGH SUNDAY. A FRONT WILL MOVE INTO THE CENTRAL PLAINS SUNDAY AFTERNOON. HIGH PRESSURE WILL BUILD INTO THE CENTRAL PLAINS SUNDAY NIGHT AND CONTINUE THROUGH MONDAY NIGHT. EARLY MORNING CONVECTION IS HANDLED WELL BY THE HRRR AND SHOULD PERSIST ACROSS THE NORTHERN AND EASTERN ZONES TILL AROUND 16Z. POPS WILL BE CHANCE AND LIKELY FOR THESE STORMS. STORM INITIATION SHOULD TAKE PLACE NEAR THE SURFACE TROUGH THIS AFTERNOON OVER EASTERN COLORADO AND EXTREME SOUTHWEST NEBRASKA. STORMS WILL DRIFT EAST INTO THE REST OF THE FA DURING THE LATE AFTERNOON/EVENING. SHEAR VALUES OF 30 TO 40 KTS WILL BE FAVORABLE FOR STORMS TO BECOME SEVERE WITH LARGE HAIL AND DAMAGING WIND. CAPE VALUES WILL RANGE FROM 1000 TO ALMOST 3000 J/KG WITH HIGHEST VALUES OVER THE NORTHWEST FA. SUBSIDENCE WILL MOVE INTO THE FA LATE SATURDAY NIGHT/SUNDAY MORNING SO POPS WILL BE NIL FOR THAT BRIEF PERIOD SUNDAY MORNING. BY SUNDAY AFTERNOON THE FRONT WILL MOVE SOUTH WITH CONVECTION ALONG AND BEHIND IT. INITIALLY STORM MOVEMENT IS NEARLY PARALLEL TO THE FRONT IN THE AFTERNOON. HOWEVER THE MODELS TAKE THE FRONT SOUTH ACROSS THE FA RATHER QUICKLY. BY EVENING STORM MOVEMENT IS ALMOST PERPENDICULAR TO THE FRONT MINIMIZING ANY TRAINING THUNDERSTORMS. PLAN TO KEEP LIKELY POPS ALONG AND BEHIND THE FRONT WITH CHANCE POPS AHEAD OF THE FRONT. OVERNIGHT POPS WILL DECREASE TO CHANCE AND SLIGHT CHANCE. ON MONDAY STORMS WILL DEVELOP OVER THE HIGHER TERRAIN IN COLORADO AND DRIFT EAST. PLAN TO KEEP AT LEAST CHANCE POPS FOR MONDAY AFTERNOON AND NIGHT. MAX TEMPERATURES TODAY WILL RISE TO THE LOWER 90S. HIGH TEMPERATURES SUNDAY RANGE FROM 85 TO 90. COOLER READINGS IN THE UPPER 70S AND LOWER 80S ARE FORECAST FOR MONDAY. MIN TEMPERATURES WILL VARY FROM THE UPPER 50S TO THE LOWER 60S. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 246 AM MDT SAT JUN 21 2014 AN UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE EXTENDED PERIOD...WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THURSDAY AND A POSSIBLE BREAK ON FRIDAY. SEVERAL SHORTWAVE TROUGHS WILL MOVE THROUGH THE CWA...AND EVEN WITH A WEAK RIDGE MOVING OVER THE CWA ON WEDNESDAY...SHORTWAVES EMBEDDED WITHIN THE FLOW WILL CONTINUE THE CHANCE FOR SHOWERS AND THUNDERSTORMS. TUESDAY THROUGH THURSDAY A LEE SURFACE LOW WILL EXIST OVER EASTERN COLORADO WITH A QUASI STATIONARY SURFACE BOUNDARY EXTENDING SOUTHWARD FROM THE LOW. INSTABILITY IS PRESENT OVER THE CWA THROUGHOUT THE EXTENDED...ALONG WITH DECENT LOW LEVEL MOISTURE...AND FAVORABLE BULK SHEAR. HOWEVER...TRYING TO TIME OUT THE PASSAGE OF EACH SHORTWAVE TROUGH AND THE POSITION OF SURFACE BOUNDARIES IS A LITTLE DIFFICULT AT THIS TIME...SO WILL HOLD OFF ON GETTING SPECIFIC WITH MENTION OF WHEN SEVERE THUNDERSTORMS WILL OCCUR EVEN THOUGH IT COULD BE LIKELY THROUGH THURSDAY. MODELS ARE NOT IN AGREEMENT WITH THE POSITION OR TIMING OF THESE FEATURES AND MODEL SPREAD ONLY INCREASES FURTHER OUT INTO THE EXTENDED. FRIDAY IS KEPT DRY FOR NOW...EVEN THOUGH THE NEW RUN OF THE ECMWF HAS A DEEP...NEGATIVELY TILTED TROUGH DIGGING FURTHER SOUTH INTO THE SOUTHERN ROCKIES AND SOUTHWESTERN UNITED STATES. THE GFS DOES NOT TAKE THE UPPER TROUGH THIS FAR SOUTH AND KEEPS IT IN THE PACIFIC NORTHWEST BUT DEVELOPS A DRYLINE THURSDAY AFTERNOON THAT WAVERS BACK WEST OVER THE CWA ON FRIDAY. AS PREVIOUSLY MENTIONED...WITH MODELS BEING IN DISAGREEMENT THROUGHOUT THE EXTENDED...CONFIDENCE IN THE EXTENDED FORECAST IS FAIRLY LOW. FOR THE MOST PART ACCEPTED THE ALLBLEND...WITH A FEW MINOR ADJUSTMENTS HERE AND THERE. TEMPERATURES WILL STEADILY INCREASE THROUGHOUT THE WEEK...WITH HIGHS IN THE LOW TO MID 80S ON TUESDAY RISING INTO THE LOW TO MID 90S BY FRIDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1110 AM MDT SAT JUN 21 2014 SHOWERS AND THUNDERSTORMS...SOME POSSIBLY SEVERE WITH LARGE HAIL AND DAMAGING WINDS...WILL INCREASE IN COVERAGE LATER THIS AFTERNOON THROUGH THE EVENING HOURS AT BOTH TERMINALS AS A WEATHER DISTURBANCE MOVES THROUGH. CURRENTLY THE BEST CHANCE IS IN THE 22Z-08Z TIME FRAME ALTHOUGH VARYING MODELS HAVE VARYING SOLUTIONS TO THIS SO LATER REFINEMENT WILL BE NEEDED. AFTER 08Z JUST SOME MID AND HIGH LEVEL CLOUDINESS EXPECTED. WINDS GUSTY FROM THE EAST/SOUTHEAST FROM TAF ISSUANCE THROUGH THE REST OF THE DAY WITH SOUTHERLY WINDS AROUND 10KTS TONIGHT. ON SUNDAY WINDS SHIFT TO THE NORTHWEST AT 10-15KTS AT KGLD AROUND 15Z WHILE REMAINING LIGHT/VARIABLE AT KMCK. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...99 SHORT TERM...FS LONG TERM...ALW AVIATION...99
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1142 AM CDT Sat Jun 21 2014 .UPDATE... Issued at 1142 AM CDT SAT JUN 21 2014 Whatever outflow boundary that was left from this morning`s convection appears to be losing definition as there is only a weak gradient in temp and dewpoint across the forecast area. Profiler data suggests that northeast KS may still be on the back side of an MCV generated from the morning convection. So weak subsidence maybe why there is not much of a CU field developing yet. Latest model trends continue to struggle with location of isolated convection due to a lack of large scale forcing or surface feature to focus convergence. Additionally differences in how deep the boundary layer mixes out has an impact on how much inhibition the models have, and the NAM now is showing weak inhibition through the afternoon. In general nothing shows strong low level convergence across the area this afternoon, except the RAP which generates an outflow from convection over the KC area. With little confidence in the RAP and no obvious forcing or lift, think the afternoon is likely to remain dry. However it is difficult to completely rule out an isolated storm so will continue to monitor trends. && .SHORT TERM...(Today and Tonight) Issued at 4 AM CDT SAT JUN 21 2014 The mid-level flow was fairly zonal across much of the CONUS this morning as a broad ridge stretched across the southern U.S. and the mid-level low shifted northward into south central Canada. However, within this zonal flow several embedded shortwaves were present, with one of those stronger waves helping to create a complex of thunderstorms over much of central and eastern Nebraska. Early this morning these thunderstorms extended southward toward the Kansas/Nebraska border and into far northern Kansas. However, the regional radar loop showed the outflow from the storms excelling well out and ahead of the line of storms, so a weakening trend has been noted in this thunderstorm activity. While much of this precipitation is expected to diminish just after sunrise, the regional radar loop at 09z was showing showers and thunderstorms over south central Nebraska extending southward into far northern Kansas. Some short range models hold this batch of precipitation together as it progresses eastward into north central Kansas before dissipating by mid morning, so will need to monitor this trend this morning. For today and tonight, several weak embedded shortwaves will continue to traverse across the northern edge of the broad mid-level ridge, which will likely skim near the Kansas/Nebraska border. The surface pattern should remain fairly unchanged through tonight with high pressure anchored over the southeastern U.S. and surface low pressure across eastern Colorado and western Kansas with a fairly stationary boundary extending into western Nebraska. With the exception of a few lingering showers and thunderstorms potentially across far northern Kansas this morning, the region is expected to remain dry through the day and into the evening hours. Models show showers and thunderstorms igniting along this stationary boundary over western Nebraska and western Kansas tonight, with this activity being further supported by a stronger embedded shortwave. Latest model trends have this precipitation advancing eastward into north central Kansas during the overnight hours into Sunday morning, so have slight to low-end chance PoPs in for north central Kansas toward extreme northeast Kansas during that time frame. With model soundings showing the cap building back in during the overnight hours, any thunderstorms that develop will likely be elevated. MUCAPE values may be upwards of 1000-2000J/kg, however the 0-6km bulk shear looks to be very weak at 20kts or less so do not anticipate severe weather with this overnight activity. Despite model soundings showing some mid and high clouds building in across the region through the day, decent south-southwesterly flow should help to keep temperatures mild in the low to mid 90s. With dewpoint temperatures remaining in the mid 60s to low 70s, could see heat indices this afternoon reaching into the upper 90s to near 100 degrees. Steady southerly flow tonight will keep low temperatures mild once again with lows in the low 70s. .LONG TERM...(Sunday through Friday) Issued at 4 AM CDT SAT JUN 21 2014 Not a lot has changed in the mid/long term forecast. The most significant weather maker appears on track to impact the area late Sunday into Monday, and then have some less certain low-end precip chances later in the week. Sunday should start with thunderstorm activity to the north in Nebraska in one or more complexes in the vicinity of a diffuse surface front. This front should become more well defined and shift to the south through the day as weak height falls spread into Kansas and a lee cyclone moves into southwest Kansas. Model guidance is consistent in bringing the front into north central Kansas by mid to late afternoon on Sunday. This should allow plenty of time for heating in advance of the best forcing and expect a broad area of moderate to strong instability across the forecast area...with some extreme instability by late afternoon near the frontal boundary. Inhibition may be reduced enough even south of the front for scattered thunderstorm development on Sunday afternoon, but this would seem to be slight chance unless some outflow can push south and enhance the convergence. Greatest precip chances should hold in the northwest 1/4 of the forecast area through the afternoon, and spread southeast during the evening/overnight hours. While there will be ample instability, the wind shear even in the presence of the incoming short wave trough will be weak...unlikely to exceed 30 kts of effective shear. This should result in multicell storm structure with some small potential for the strongest storms to produce marginally severe hail or periods of damaging winds. Widespread severe weather is unlikely. This storm system will be comprised of more than one weak short wave moving through the weak broad trough, and thus expect multiple rounds of thunderstorms through Monday afternoon. PWAT values are likely to exceed 1.5 inches and may be closer to 2 inches at times...especially Sunday night. The weak wind fields will promote a relatively slow storm motion while a moderate low level jet could orient favorably for periods of training storms. It`s not an optimal setup, but some ingredients are present for a heavy rain event, possibly enough to lead to some flooding. The trough axis should pass through the area by late Monday, with a dry period expected through Tuesday. How long this dry period lasts is uncertain as there are indications of additional pieces of upper level energy impacting the central Plains by Tuesday night into Wednesday. Uncertainty increases further by late in the week as there are indications of a deeper trough building into the western CONUS with southwest flow aloft and lead short waves ejecting across the Plains. Forecasting the strength of the trough and a southeastern CONUS ridge is where model guidance diverges at this time, and will have a pronounced impact on the local forecast. All told, precip chances do not look substantial, but are warranted for much of the Thurs/Fri period. A warming trend in temperatures as well as increased low level moisture is also expected for Thursday and Friday. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1142 AM CDT SAT JUN 21 2014 Chances for TS to impact the terminals appears to be relatively low due to no feature to focus convection. Therefore have kept a VFR forecast through the period. For more detail, see the update section above. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...Wolters SHORT TERM...Hennecke LONG TERM...Barjenbruch AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS GOODLAND KS
900 AM MDT SAT JUN 21 2014 .UPDATE... ISSUED AT 900 AM MDT SAT JUN 21 2014 UPDATE REQUIRED FOR THE REST OF THE DAY TO BETTER REPRESENT CURRENT RADAR TRENDS AND THE NEXT 8-9 HOURS OF TEMPS/DP/WINDS/POP AND WX. SHOWERS AND THUNDERSTORMS THAT HAVE BEEN LOCATED ALONG THE KS/NE BORDER THIS MORNING SLOWLY STARTING TO LOSE INTENSITY AND AREAL COVERAGE AND THIS TREND SHOULD CONTINUE THE REST OF THE MORNING. DURING THE AFTERNOON CURRENTLY EXPECTING A SFC TROUGH TO SET UP NEAR/JUST EAST OF THE CO/KS BORDER. MAY HAVE A FEW STORMS DEVELOP ALONG THIS BY MID/LATE AFTERNOON WITH A SLOW EASTWARD PUSH TO THE EAST AS A STRONG WEATHER DISTURBANCE AND BETTER UPPER JET DIVERGENCE MOVES IN TO EASTERN COLORADO. THIS SHOULD BE ENOUGH TO CREATE SOME STRONG/SEVERE STORMS IN EASTERN COLORADO AND ALONG THE SFC TROUGH IN WESTERN KANSAS/SOUTHWEST NEBRASKA. LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY THREATS. HIGH TEMPERATURES GENERALLY IN THE UPPER 80S TO LOW 90S IN EASTERN COLORADO WITH LOW TO MID 90S EAST OF THE BORDER. MAY SEE SOME UPPER 90S...ESPECIALLY ACROSS THE EAST THROUGH SOUTH WHERE IMPACTS OF APPROACHING CIRRUS FROM THE WEST MAY BE LESS. && .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 246 AM MDT SAT JUN 21 2014 A RIDGE OVER THE PLAINS WILL FLATTEN SOME TONIGHT. FLOW WILL BECOME ZONAL ON SUNDAY AND THEN TURN NORTHWEST MONDAY/MONDAY NIGHT. A SURFACE TROUGH WILL BE NEAR NORTHEAST COLORADO TODAY THROUGH SUNDAY. A FRONT WILL MOVE INTO THE CENTRAL PLAINS SUNDAY AFTERNOON. HIGH PRESSURE WILL BUILD INTO THE CENTRAL PLAINS SUNDAY NIGHT AND CONTINUE THROUGH MONDAY NIGHT. EARLY MORNING CONVECTION IS HANDLED WELL BY THE HRRR AND SHOULD PERSIST ACROSS THE NORTHERN AND EASTERN ZONES TILL AROUND 16Z. POPS WILL BE CHANCE AND LIKELY FOR THESE STORMS. STORM INITIATION SHOULD TAKE PLACE NEAR THE SURFACE TROUGH THIS AFTERNOON OVER EASTERN COLORADO AND EXTREME SOUTHWEST NEBRASKA. STORMS WILL DRIFT EAST INTO THE REST OF THE FA DURING THE LATE AFTERNOON/EVENING. SHEAR VALUES OF 30 TO 40 KTS WILL BE FAVORABLE FOR STORMS TO BECOME SEVERE WITH LARGE HAIL AND DAMAGING WIND. CAPE VALUES WILL RANGE FROM 1000 TO ALMOST 3000 J/KG WITH HIGHEST VALUES OVER THE NORTHWEST FA. SUBSIDENCE WILL MOVE INTO THE FA LATE SATURDAY NIGHT/SUNDAY MORNING SO POPS WILL BE NIL FOR THAT BRIEF PERIOD SUNDAY MORNING. BY SUNDAY AFTERNOON THE FRONT WILL MOVE SOUTH WITH CONVECTION ALONG AND BEHIND IT. INITIALLY STORM MOVEMENT IS NEARLY PARALLEL TO THE FRONT IN THE AFTERNOON. HOWEVER THE MODELS TAKE THE FRONT SOUTH ACROSS THE FA RATHER QUICKLY. BY EVENING STORM MOVEMENT IS ALMOST PERPENDICULAR TO THE FRONT MINIMIZING ANY TRAINING THUNDERSTORMS. PLAN TO KEEP LIKELY POPS ALONG AND BEHIND THE FRONT WITH CHANCE POPS AHEAD OF THE FRONT. OVERNIGHT POPS WILL DECREASE TO CHANCE AND SLIGHT CHANCE. ON MONDAY STORMS WILL DEVELOP OVER THE HIGHER TERRAIN IN COLORADO AND DRIFT EAST. PLAN TO KEEP AT LEAST CHANCE POPS FOR MONDAY AFTERNOON AND NIGHT. MAX TEMPERATURES TODAY WILL RISE TO THE LOWER 90S. HIGH TEMPERATURES SUNDAY RANGE FROM 85 TO 90. COOLER READINGS IN THE UPPER 70S AND LOWER 80S ARE FORECAST FOR MONDAY. MIN TEMPERATURES WILL VARY FROM THE UPPER 50S TO THE LOWER 60S. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 246 AM MDT SAT JUN 21 2014 AN UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE EXTENDED PERIOD...WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THURSDAY AND A POSSIBLE BREAK ON FRIDAY. SEVERAL SHORTWAVE TROUGHS WILL MOVE THROUGH THE CWA...AND EVEN WITH A WEAK RIDGE MOVING OVER THE CWA ON WEDNESDAY...SHORTWAVES EMBEDDED WITHIN THE FLOW WILL CONTINUE THE CHANCE FOR SHOWERS AND THUNDERSTORMS. TUESDAY THROUGH THURSDAY A LEE SURFACE LOW WILL EXIST OVER EASTERN COLORADO WITH A QUASI STATIONARY SURFACE BOUNDARY EXTENDING SOUTHWARD FROM THE LOW. INSTABILITY IS PRESENT OVER THE CWA THROUGHOUT THE EXTENDED...ALONG WITH DECENT LOW LEVEL MOISTURE...AND FAVORABLE BULK SHEAR. HOWEVER...TRYING TO TIME OUT THE PASSAGE OF EACH SHORTWAVE TROUGH AND THE POSITION OF SURFACE BOUNDARIES IS A LITTLE DIFFICULT AT THIS TIME...SO WILL HOLD OFF ON GETTING SPECIFIC WITH MENTION OF WHEN SEVERE THUNDERSTORMS WILL OCCUR EVEN THOUGH IT COULD BE LIKELY THROUGH THURSDAY. MODELS ARE NOT IN AGREEMENT WITH THE POSITION OR TIMING OF THESE FEATURES AND MODEL SPREAD ONLY INCREASES FURTHER OUT INTO THE EXTENDED. FRIDAY IS KEPT DRY FOR NOW...EVEN THOUGH THE NEW RUN OF THE ECMWF HAS A DEEP...NEGATIVELY TILTED TROUGH DIGGING FURTHER SOUTH INTO THE SOUTHERN ROCKIES AND SOUTHWESTERN UNITED STATES. THE GFS DOES NOT TAKE THE UPPER TROUGH THIS FAR SOUTH AND KEEPS IT IN THE PACIFIC NORTHWEST BUT DEVELOPS A DRYLINE THURSDAY AFTERNOON THAT WAVERS BACK WEST OVER THE CWA ON FRIDAY. AS PREVIOUSLY MENTIONED...WITH MODELS BEING IN DISAGREEMENT THROUGHOUT THE EXTENDED...CONFIDENCE IN THE EXTENDED FORECAST IS FAIRLY LOW. FOR THE MOST PART ACCEPTED THE ALLBLEND...WITH A FEW MINOR ADJUSTMENTS HERE AND THERE. TEMPERATURES WILL STEADILY INCREASE THROUGHOUT THE WEEK...WITH HIGHS IN THE LOW TO MID 80S ON TUESDAY RISING INTO THE LOW TO MID 90S BY FRIDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 457 AM MDT SAT JUN 21 2014 CURRENT RADAR WITH RETURNS FROM THUNDERSTORMS, WITH ONE HEADING FOR KMCK AND SHOULD BE THERE BY 12Z. ADDITIONAL STORMS ARE EXPECTED LATER THIS AFTERNOON AND EVENING. SOME MVFR CONDITIONS ARE POSSIBLE NEAR ANY STORMS, OTHERWISE VFR WILL PREVAIL AT BOTH TERMINALS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...99 SHORT TERM...FS LONG TERM...ALW AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
502 AM MDT SAT JUN 21 2014 .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 246 AM MDT SAT JUN 21 2014 A RIDGE OVER THE PLAINS WILL FLATTEN SOME TONIGHT. FLOW WILL BECOME ZONAL ON SUNDAY AND THEN TURN NORTHWEST MONDAY/MONDAY NIGHT. A SURFACE TROUGH WILL BE NEAR NORTHEAST COLORADO TODAY THROUGH SUNDAY. A FRONT WILL MOVE INTO THE CENTRAL PLAINS SUNDAY AFTERNOON. HIGH PRESSURE WILL BUILD INTO THE CENTRAL PLAINS SUNDAY NIGHT AND CONTINUE THROUGH MONDAY NIGHT. EARLY MORNING CONVECTION IS HANDLED WELL BY THE HRRR AND SHOULD PERSIST ACROSS THE NORTHERN AND EASTERN ZONES TILL AROUND 16Z. POPS WILL BE CHANCE AND LIKELY FOR THESE STORMS. STORM INITIATION SHOULD TAKE PLACE NEAR THE SURFACE TROUGH THIS AFTERNOON OVER EASTERN COLORADO AND EXTREME SOUTHWEST NEBRASKA. STORMS WILL DRIFT EAST INTO THE REST OF THE FA DURING THE LATE AFTERNOON/EVENING. SHEAR VALUES OF 30 TO 40 KTS WILL BE FAVORABLE FOR STORMS TO BECOME SEVERE WITH LARGE HAIL AND DAMAGING WIND. CAPE VALUES WILL RANGE FROM 1000 TO ALMOST 3000 J/KG WITH HIGHEST VALUES OVER THE NORTHWEST FA. SUBSIDENCE WILL MOVE INTO THE FA LATE SATURDAY NIGHT/SUNDAY MORNING SO POPS WILL BE NIL FOR THAT BRIEF PERIOD SUNDAY MORNING. BY SUNDAY AFTERNOON THE FRONT WILL MOVE SOUTH WITH CONVECTION ALONG AND BEHIND IT. INITIALLY STORM MOVEMENT IS NEARLY PARALLEL TO THE FRONT IN THE AFTERNOON. HOWEVER THE MODELS TAKE THE FRONT SOUTH ACROSS THE FA RATHER QUICKLY. BY EVENING STORM MOVEMENT IS ALMOST PERPENDICULAR TO THE FRONT MINIMIZING ANY TRAINING THUNDERSTORMS. PLAN TO KEEP LIKELY POPS ALONG AND BEHIND THE FRONT WITH CHANCE POPS AHEAD OF THE FRONT. OVERNIGHT POPS WILL DECREASE TO CHANCE AND SLIGHT CHANCE. ON MONDAY STORMS WILL DEVELOP OVER THE HIGHER TERRAIN IN COLORADO AND DRIFT EAST. PLAN TO KEEP AT LEAST CHANCE POPS FOR MONDAY AFTERNOON AND NIGHT. MAX TEMPERATURES TODAY WILL RISE TO THE LOWER 90S. HIGH TEMPERATURES SUNDAY RANGE FROM 85 TO 90. COOLER READINGS IN THE UPPER 70S AND LOWER 80S ARE FORECAST FOR MONDAY. MIN TEMPERATURES WILL VARY FROM THE UPPER 50S TO THE LOWER 60S. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 246 AM MDT SAT JUN 21 2014 AN UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE EXTENDED PERIOD...WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THURSDAY AND A POSSIBLE BREAK ON FRIDAY. SEVERAL SHORTWAVE TROUGHS WILL MOVE THROUGH THE CWA...AND EVEN WITH A WEAK RIDGE MOVING OVER THE CWA ON WEDNESDAY...SHORTWAVES EMBEDDED WITHIN THE FLOW WILL CONTINUE THE CHANCE FOR SHOWERS AND THUNDERSTORMS. TUESDAY THROUGH THURSDAY A LEE SURFACE LOW WILL EXIST OVER EASTERN COLORADO WITH A QUASI STATIONARY SURFACE BOUNDARY EXTENDING SOUTHWARD FROM THE LOW. INSTABILITY IS PRESENT OVER THE CWA THROUGHOUT THE EXTENDED...ALONG WITH DECENT LOW LEVEL MOISTURE...AND FAVORABLE BULK SHEAR. HOWEVER...TRYING TO TIME OUT THE PASSAGE OF EACH SHORTWAVE TROUGH AND THE POSITION OF SURFACE BOUNDARIES IS A LITTLE DIFFICULT AT THIS TIME...SO WILL HOLD OFF ON GETTING SPECIFIC WITH MENTION OF WHEN SEVERE THUNDERSTORMS WILL OCCUR EVEN THOUGH IT COULD BE LIKELY THROUGH THURSDAY. MODELS ARE NOT IN AGREEMENT WITH THE POSITION OR TIMING OF THESE FEATURES AND MODEL SPREAD ONLY INCREASES FURTHER OUT INTO THE EXTENDED. FRIDAY IS KEPT DRY FOR NOW...EVEN THOUGH THE NEW RUN OF THE ECMWF HAS A DEEP...NEGATIVELY TILTED TROUGH DIGGING FURTHER SOUTH INTO THE SOUTHERN ROCKIES AND SOUTHWESTERN UNITED STATES. THE GFS DOES NOT TAKE THE UPPER TROUGH THIS FAR SOUTH AND KEEPS IT IN THE PACIFIC NORTHWEST BUT DEVELOPS A DRYLINE THURSDAY AFTERNOON THAT WAVERS BACK WEST OVER THE CWA ON FRIDAY. AS PREVIOUSLY MENTIONED...WITH MODELS BEING IN DISAGREEMENT THROUGHOUT THE EXTENDED...CONFIDENCE IN THE EXTENDED FORECAST IS FAIRLY LOW. FOR THE MOST PART ACCEPTED THE ALLBLEND...WITH A FEW MINOR ADJUSTMENTS HERE AND THERE. TEMPERATURES WILL STEADILY INCREASE THROUGHOUT THE WEEK...WITH HIGHS IN THE LOW TO MID 80S ON TUESDAY RISING INTO THE LOW TO MID 90S BY FRIDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 457 AM MDT SAT JUN 21 2014 CURRENT RADAR WITH RETURNS FROM THUNDERSTORMS, WITH ONE HEADING FOR KMCK AND SHOULD BE THERE BY 12Z. ADDITIONAL STORMS ARE EXPECTED LATER THIS AFTERNOON AND EVENING. SOME MVFR CONDITIONS ARE POSSIBLE NEAR ANY STORMS, OTHERWISE VFR WILL PREVAIL AT BOTH TERMINALS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...FS LONG TERM...ALW AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
249 AM MDT SAT JUN 21 2014 .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 246 AM MDT SAT JUN 21 2014 A RIDGE OVER THE PLAINS WILL FLATTEN SOME TONIGHT. FLOW WILL BECOME ZONAL ON SUNDAY AND THEN TURN NORTHWEST MONDAY/MONDAY NIGHT. A SURFACE TROUGH WILL BE NEAR NORTHEAST COLORADO TODAY THROUGH SUNDAY. A FRONT WILL MOVE INTO THE CENTRAL PLAINS SUNDAY AFTERNOON. HIGH PRESSURE WILL BUILD INTO THE CENTRAL PLAINS SUNDAY NIGHT AND CONTINUE THROUGH MONDAY NIGHT. EARLY MORNING CONVECTION IS HANDLED WELL BY THE HRRR AND SHOULD PERSIST ACROSS THE NORTHERN AND EASTERN ZONES TILL AROUND 16Z. POPS WILL BE CHANCE AND LIKELY FOR THESE STORMS. STORM INITIATION SHOULD TAKE PLACE NEAR THE SURFACE TROUGH THIS AFTERNOON OVER EASTERN COLORADO AND EXTREME SOUTHWEST NEBRASKA. STORMS WILL DRIFT EAST INTO THE REST OF THE FA DURING THE LATE AFTERNOON/EVENING. SHEAR VALUES OF 30 TO 40 KTS WILL BE FAVORABLE FOR STORMS TO BECOME SEVERE WITH LARGE HAIL AND DAMAGING WIND. CAPE VALUES WILL RANGE FROM 1000 TO ALMOST 3000 J/KG WITH HIGHEST VALUES OVER THE NORTHWEST FA. SUBSIDENCE WILL MOVE INTO THE FA LATE SATURDAY NIGHT/SUNDAY MORNING SO POPS WILL BE NIL FOR THAT BRIEF PERIOD SUNDAY MORNING. BY SUNDAY AFTERNOON THE FRONT WILL MOVE SOUTH WITH CONVECTION ALONG AND BEHIND IT. INITIALLY STORM MOVEMENT IS NEARLY PARALLEL TO THE FRONT IN THE AFTERNOON. HOWEVER THE MODELS TAKE THE FRONT SOUTH ACROSS THE FA RATHER QUICKLY. BY EVENING STORM MOVEMENT IS ALMOST PERPENDICULAR TO THE FRONT MINIMIZING ANY TRAINING THUNDERSTORMS. PLAN TO KEEP LIKELY POPS ALONG AND BEHIND THE FRONT WITH CHANCE POPS AHEAD OF THE FRONT. OVERNIGHT POPS WILL DECREASE TO CHANCE AND SLIGHT CHANCE. ON MONDAY STORMS WILL DEVELOP OVER THE HIGHER TERRAIN IN COLORADO AND DRIFT EAST. PLAN TO KEEP AT LEAST CHANCE POPS FOR MONDAY AFTERNOON AND NIGHT. MAX TEMPERATURES TODAY WILL RISE TO THE LOWER 90S. HIGH TEMPERATURES SUNDAY RANGE FROM 85 TO 90. COOLER READINGS IN THE UPPER 70S AND LOWER 80S ARE FORECAST FOR MONDAY. MIN TEMPERATURES WILL VARY FROM THE UPPER 50S TO THE LOWER 60S. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 246 AM MDT SAT JUN 21 2014 AN UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE EXTENDED PERIOD...WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THURSDAY AND A POSSIBLE BREAK ON FRIDAY. SEVERAL SHORTWAVE TROUGHS WILL MOVE THROUGH THE CWA...AND EVEN WITH A WEAK RIDGE MOVING OVER THE CWA ON WEDNESDAY...SHORTWAVES EMBEDDED WITHIN THE FLOW WILL CONTINUE THE CHANCE FOR SHOWERS AND THUNDERSTORMS. TUESDAY THROUGH THURSDAY A LEE SURFACE LOW WILL EXIST OVER EASTERN COLORADO WITH A QUASI STATIONARY SURFACE BOUNDARY EXTENDING SOUTHWARD FROM THE LOW. INSTABILITY IS PRESENT OVER THE CWA THROUGHOUT THE EXTENDED...ALONG WITH DECENT LOW LEVEL MOISTURE...AND FAVORABLE BULK SHEAR. HOWEVER...TRYING TO TIME OUT THE PASSAGE OF EACH SHORTWAVE TROUGH AND THE POSITION OF SURFACE BOUNDARIES IS A LITTLE DIFFICULT AT THIS TIME...SO WILL HOLD OFF ON GETTING SPECIFIC WITH MENTION OF WHEN SEVERE THUNDERSTORMS WILL OCCUR EVEN THOUGH IT COULD BE LIKELY THROUGH THURSDAY. MODELS ARE NOT IN AGREEMENT WITH THE POSITION OR TIMING OF THESE FEATURES AND MODEL SPREAD ONLY INCREASES FURTHER OUT INTO THE EXTENDED. FRIDAY IS KEPT DRY FOR NOW...EVEN THOUGH THE NEW RUN OF THE ECMWF HAS A DEEP...NEGATIVELY TILTED TROUGH DIGGING FURTHER SOUTH INTO THE SOUTHERN ROCKIES AND SOUTHWESTERN UNITED STATES. THE GFS DOES NOT TAKE THE UPPER TROUGH THIS FAR SOUTH AND KEEPS IT IN THE PACIFIC NORTHWEST BUT DEVELOPS A DRYLINE THURSDAY AFTERNOON THAT WAVERS BACK WEST OVER THE CWA ON FRIDAY. AS PREVIOUSLY MENTIONED...WITH MODELS BEING IN DISAGREEMENT THROUGHOUT THE EXTENDED...CONFIDENCE IN THE EXTENDED FORECAST IS FAIRLY LOW. FOR THE MOST PART ACCEPTED THE ALLBLEND...WITH A FEW MINOR ADJUSTMENTS HERE AND THERE. TEMPERATURES WILL STEADILY INCREASE THROUGHOUT THE WEEK...WITH HIGHS IN THE LOW TO MID 80S ON TUESDAY RISING INTO THE LOW TO MID 90S BY FRIDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1147 PM MDT FRI JUN 20 2014 VFR CONDITIONS WILL PREVAIL THOUGH THE PERIOD AND SOUTHERLY WINDS SHOULD GENERALLY REMAIN IN THE 10-15KT RANGE AT BOTH KGLD AND KMCK. THERE COULD BE SOME GUSTS AROUND 20KT AT EITHER TERMINAL LATE AFTERNOON/EARLY EVENING SATURDAY...HOWEVER THERE IS SOME MODEL SPREAD ON SURFACE GRADIENT AND OVERLY CONFIDENCE IN THIS ISNT HIGH. THUNDERSTORMS HAVE REDEVELOPED OVER NE COLORADO...HOWEVER THEY HAVE STRUGGLED TO MAKE MUCH EASTWARD PROGRESS AND SHORT RANGE GUIDANCE FAVORS THIS ACTIVITY REMAINING OUTSIDE THE VICINITY OF EITHER TERMINAL DURING THE EARLY TAF PERIOD. ADDITIONAL THUNDERSTORM IS EXPECTED TO DEVELOP OVER EASTERN COLORADO SATURDAY AFTERNOON AND INCREASE IN COVERAGE AT BOTH TERMINALS THROUGH SATURDAY EVENING. I INTRODUCED A PREVAILING THUNDER GROUP AT BOTH TERMINALS FOR PERIODS WITH BEST MODEL OVERLAP IN TIMING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...FS LONG TERM...ALW AVIATION...DR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
615 PM EDT Sat Jun 21 2014 ...Forecast Update... Issued at 614 PM EDT Sat Jun 21 2014 Quick update this evening to account for ongoing trends. Despite a few very isolated light showers, precipitation has ended across southern KY. Therefore, will remove precip mention from the forecast for the remainder of the evening hours. Attention will then turn to the northwest as a line of showers and thunderstorms continues to develop across IL/MO. The main forecast challenge tonight will be just how far east that convection makes it. Given it will be fighting much drier air that has protruded into southern IN and into southern IL, think this convection will likely struggle as it pushes east. However, the latest HRRR which has a good handle on the current convection, does bring a weakening line into southern IN around 06Z overnight. Given the drier air firmly in place, will continue with a dry forecast but will continue to monitor trends over the next few hours. .SHORT TERM (Now through Sunday Night)... Issued at 300 PM EDT Sat Jun 21 2014 The upper air pattern shows a progressive relatively flat flow at 500mb confined generally to the northern tier of states. Weak northwest flow currently over the northern Ohio Valley will become weaker as ridging is forecast to develop across the Lower Mississippi Valley by late Sunday, extending northeastwards through southern Indiana. Expect only a few flat cumulus this afternoon along and north of Interstate 64 as the shortwave that brought scattered thunderstorms earlier this morning to the Lake Cumberland Region moves farther southeast. Any additional isolated thunderstorms through late afternoon will stay along and southeast of the Cumberland Parkway. Expect mostly clear skies tonight with humid conditions and light winds. Some patchy fog may once again develop across southern Indiana and the Bluegrass Region, although not to the extent of earlier this morning. Lows tonight will range from the mid 60s across the Bluegrass and southern Indiana to near 70 elsewhere. Despite adequate moisture and quite unstable conditions developing Sunday afternoon, ridging aloft will inhibit any widespread convection. Think that scattered thunderstorms may develop farther north across Illinois and Indiana, with isolated storms at best along and north of the Ohio River. Expect south central Kentucky to stay dry. Highs Sunday will range from the upper 80s northeast to the lower 90s southwest. Light south winds will develop Sunday afternoon. .LONG TERM (Monday through Saturday)... Issued at 255 PM EDT Sat Jun 21 2014 Fairly typical summertime conditions expected for most of the upcoming week, with a low-amplitude and somewhat progressive pattern aloft. Shortwave ridging on Monday will most likely allow for the warmest temps of the week. However, the pattern is still just flat enough and heights not getting into legitimate heat wave territory, so expect temps to reach the lower 90s in most spots. This stays in line with the more consistent and slightly cooler NAM MOS. Chance POPs will re-enter the picture Monday afternoon as the ridging begins to gradually weaken. Best chance for showers and storms will be Tuesday into Tuesday night, with the passage of an upper shortwave trof. High PWATs will support a heavy rain and pulse wind threat. The rest of the week will not see any real pattern change, but just warm and humid conditions with isolated/scattered storms each day, mainly in the afternoons. Pattern aloft starts to amplify toward the end of the week with a ridge nosing up into the Upper Midwest. This bears watch for a possible break in our daily convection and temps possibly punching back into the 90s at some point next weekend. && .AVIATION (18Z TAF Update)... Issued at 125 PM EDT Sat Jun 21 2014 Partly cloudy skies with some fair-weather cumulus will continue this afternoon, clearing by early to mid evening. Overnight, expect mostly clear skies and light patchy ground fog which will not become nearly as dense as it became earlier this morning. Winds will stay northerly at 5 to 10 mph through early evening, then become calm or light easterly overnight, and eventually become very light southerly Sunday afternoon. Widely scattered thunderstorms are possible Sunday afternoon and evening. However coverage and confidence are low and will not put in TAFs at this time. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........KJD Short Term.....JSD Long Term......RAS Aviation.......JSD
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
901 PM CDT SUN JUN 22 2014 .UPDATE... 00Z UPPER AIR ANALYSIS INDICATES H5 UPPER TROUGH OVER ERN TX AND IS ALSO EVIDENT IN WATER VAPOR IMAGERY/RUC WIND ANALYSIS. ANOTHER WEAK S/WV AND FLOW ALOFT IS AIDING IN THE CURRENT SHOWERS/STORMS DEVELOPING IN THE W/SW AREAS. LEFT SOME POPS IN THE W/SW UNTIL 04Z. THE DIURNAL ACTIVITY SHOULD WEAKEN AND WE SHOULD BE CLEAR OF SHOWERS/STORMS FOR A FEW HOURS...WHICH IS INDICATED IN MOST HI-RES GUIDANCE INCLUDING HRRR/ARW. PUT SOME POPS IN AFTER 09Z IN THE W/SW AS THE S/WV TO THE W APPROACHES THE AREA AND SOME SHOWERS WILL BE POSSIBLE IN THESE AREAS. CLOUDS SHOULD THIN SOMEWHAT IN THE E/NE AND LEAD TO COOLER CONDITIONS IN THE E. WENT SLIGHTLY WARMER THAN MAV IN THE W DUE TO MID/HIGH CLOUD DEBRIS WHILE DECREASING SLIGHTLY IN THE E DUE TO LESS CLOUDS. TONIGHT WILL BE SIMILAR THAT SOME PATCHY FOG IS POSSIBLE BUT MAINLY GROUND FOG IN AREAS THAT RECEIVED RAINFALL. FORECAST RUC SOUNDINGS AND LOWER PWATS WILL LEAD TO LOWER CHANCES OF FOG. THUS...NOT GOING TO PUT PATCHY FOG IN THE GRIDS FOR NOW. OVERALL..ADJUSTED HOURLY TEMPS/DEWPOINTS/SKY COVER/POPS TO CURRENT TRENDS. REST OF THE FORECAST IS ON TRACK. /DC/ && .AVIATION... SHRA/TSRA ARE CONTINUING TO DIMINISH THIS EVENING. EXPECT PATCHY AREAS OF MVFR CATEGORY FOG TONIGHT LASTING UNTIL SHORTLY AFTER DAYBREAK MONDAY. THE LATEST HRRR SUGGESTS LOW STRATUS COULD DEVELOP IN THE PIB/HBG AREA...BUT EXPECT MID/HIGH LEVEL CLOUDS TO BE MOST PREVALENT. THE GREATEST REGENERATION OF SHRA/TSRA SHOULD BEGIN LATE MONDAY MORNING OVER MOST OF THE AREA...PERSISTING INTO EARLY MONDAY EVENING. /EC/ && .PREV DISCUSSION... /ISSUED 238 PM CDT SUN JUN 22 2014/ SHORT TERM...ACTIVE CONVECTIVE AFTERNOON UNDERWAY OVER THE CWA AT THE MOMENT. THUNDERSTORMS APPEAR TO HAVE DEVELOPED AROUND THE LEADING PERIPHERY OF 300 MB 35 KNOT JET STREAK...AS ADVERTISED BY THE RAP. THIS DEVELOPMENT OCCURRING OVER MAINLY EASTERN HALF WHILE THE WESTERN PORTION APPEARS TO BE BENEFITTING FROM WEAK SHORTWAVE RIDGING. WHILE THE MAJORITY OF EVENING CONVECTION LOOKS TO OCCUR OVER THE FAR EAST AND SOUTHEAST...APPROACHING SHORTWAVE OVER EAST TX AND OVERALL INCREASING TROFFINESS SHOULD ALLOW CONVECTIVE DEVELOPMENT TO RECUR AFTER MIDNIGHT OVER ALL AREAS AS ADVERTISED BY MODELS. AS IS THE CASE TODAY...PW VALUES MONDAY NEAR 2 INCHES WILL MAKE THUNDERSTORMS VERY EFFICIENT RAIN MAKERS AND SLOW MOVEMENT MAY ALLOW FOR LOCALIZED SHORT TERM PONDING/FLOODING TO OCCUR. NOT GOING TO RULE OUT A FEW WET MICROBURSTS AS WELL. WHILE VERTICAL TOTALS/LAPSE RATES ARE NOT AS IMPRESSIVE MONDAY AS TODAY...PRECIP LOADING MAY STILL BE SUFFICIENT ENOUGH TO DRAG DOWN SOME DECENT WIND SPEEDS. DUE TO EXPECTED SPARSE OCCURRENCE OF THIS...HOWEVER...WILL LEAVE OUT OF THE HWO. SHORTWAVE RIDGING LOOKS TO LIMIT CONVECTIVE POTENTIAL TUESDAY AS PW VALUES FALL BACK TO AROUND 1.5 INCHES FOR THE AREA. THIS LOOKS TO BE SHORT-LIVED...HOWEVER...AS A MORE POTENT WAVE MOVING ACROSS THE MID MS VALLEY TUESDAY AFTERNOON/EVENING WILL DRAG A WEAK COLD FRONT INTO NORTHERN PORTIONS OF THE AREA AFTER MIDNIGHT TUESDAY NIGHT. THUS...WILL KEEP SCATTERED POPS RUNNING OVERNIGHT IN THE NORTH. MOS TEMPS WERE GENERALLY AGREEABLE...HOWEVER...SHAVED HIGHS A COUPLE DEGREES TUESDAY AS MOS CAME IN A LITTLE WARM IN THE MID 90S. /26/ LONG TERM...WEDNESDAY THROUGH NEXT SUNDAY...DURING THE MIDDLE PORTION OF THE WEEK...UPPER LEVEL FLOW WILL REMAIN RELATIVELY WEAK AND PRIMARILY ZONAL. A WEAK SURFACE HIGH WILL REMAIN SITUATED OVER THE NORTHERN GULF...THOUGH THIS FEATURE IS UNLIKELY TO DO MUCH TO DISCOURAGE THE SUMMERTIME DIURNAL CONVECTIVE CYCLE WHICH IS FIRMLY ENTRENCHED ACROSS THE AREA. 00Z GFS/ECMWF RUNS DEPICT A SHORTWAVE TROUGH MOVING ACROSS THE SOUTHERN PLAINS TOWARD THE MID MS VALLEY WED INTO THURS...WHICH WOULD LIKELY SERVE TO ENHANCE PRECIP COVERAGE DURING THAT TIME FRAME. POPS WERE TRENDED TOWARD ECMWF OUTPUT...WHICH SEEMED TO HAVE A BETTER GRASP OF THESE FEATURES. FROM THE END OF THE WEEK INTO THE WEEKEND GUIDANCE...ESPECIALLY THE ECWMF...INDICATES BUILDING MID/UPPER LEVEL RIDGING. THIS WOULD SUGGEST A DECREASE IN DAILY CONVECTIVE ACTIVITY BACK TO MORE SEASONABLE LEVELS. ISOLATED PRECIPITATION WOULD STILL BE AROUND... BUT WITH UPPER FLOW REMAINING WEAK AND MID LEVEL TEMPS WARMING UP UNDER THE RIDGE...MUCH OF THE CONVECTIVE ACTIVITY WOULD BE SUPPRESSED. /DL/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 71 89 70 92 / 15 63 21 23 MERIDIAN 69 88 68 91 / 14 74 40 35 VICKSBURG 71 89 69 92 / 18 49 20 19 HATTIESBURG 72 88 71 92 / 16 63 20 29 NATCHEZ 71 87 70 90 / 22 57 19 19 GREENVILLE 73 90 70 91 / 17 52 23 26 GREENWOOD 72 89 70 91 / 14 67 33 26 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ DC/EC/26/DL
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
400 PM CDT Sat Jun 21 2014 .DISCUSSION... Issued at 359 PM CDT SAT JUN 21 2014 What else would one expect for the official first day of summer other than an uncapped tropical airmass defined by high CAPEs and weak shear with isolated convection along weak boundaries. Very weak and isolated convection continues to sputter across northern MO this afternoon in a region of weak h8 convergence. Increasing convection is noted in a region of moderate h8 moisture convergence which extends southwest from west central IL cluster into the east central CWA. HRRR has been picking out this general area for most of today. Will focus higher PoPs for the late afternoon and early evening hours this area. A small MCV over south central NE left over from earlier convection is drifting east towards slightly higher MLCAPEs around 2000 J/kg. Will insert low chance PoPs for this evening for nw and north central MO for possible convective development. Last several runs of the HRRR generates scattered convection this area. Expect another complex convective scenario tonight. Current convection over the NE Panhandle may eventually merge with another nocturnal MCS that rolls off the CO Front Range and heads east. Will throw in some PoPs over northwest MO towards Sunday morning to cover the possibility of a dying MCS reaching the CWA. Continued very warm and humid on Sunday with above average temperatures. Low confidence on placement of PoPs as any outflow boundaries left over from tonights convection will play a key role. Sunday night into Monday still holds the highest PoPs during this forecast period. While the models have started to diverge on where another nocturnal MCS will track there is good consensus that a cold front moving southeast through NE/IA/KS will play a pivotal role. Have had to lower qpf during this period as confidence on a large MCS moving through the CWA has diminished. But should see good coverage of convection with the front. High precipitable water values are a concern should storms crawl through or back build along the front. So, later forecasts may need to ramp qpf back up. While Tuesday looks dry and a tad cooler behind the front weak embedded disturbances within the quasi-zonal pattern will provide alot of uncertainty on timing and location of any convection for Wednesday/Wednesday night. The upper pattern evolves for the latter half of the week as an upper trough pushes through the intermountain region. The backing flow downstream will enable a southwesterly fetch to spread through the Central Plains and Mid MO Valley. Should see a slight uptick in temperatures and humidity with warmer air aloft spreading into the CWA and forcing any convection to become elevated and more nocturnal. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Issued at 1238 PM CDT SAT JUN 21 2014 Will maintain the going VFR forecast. Isolated to scattered convection possible across northern MO this afternoon. Activity should remain north of the terminals, especially KMCI/KMKC. Will be monitoring the current activity moving east into far northwest MO. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...MJ DISCUSSION...MJ AVIATION...MJ
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
706 PM CDT SUN JUN 22 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 341 PM CDT SUN JUN 22 2014 AT 19Z...WATER VAPOR SHOWED QUASI-ZONAL FLOW ACROSS MUCH OF THE CONUS WITH AN UPPER LEVEL LOW SPINNING OVER THE CENTRAL SASKATCHEWAN/MANITOBA BORDER. MULTIPLE WEAK SHORTWAVES COULD BE PICKED OUT MOVING ACROSS THE ROCKIES...FROM MONTANA DOWN THROUGH NEW MEXICO. THE STRONGER SHORTWAVE WAS SEEN OVER WESTERN COLORADO AT MID AFTERNOON WHICH WILL IMPACT THE FORECAST FOR TONIGHT...WITH THE SECOND MORE DISTINCT SHORTWAVE SEEN OVER EASTERN IDAHO...WHICH WILL IMPACT THE FORECAST FOR MONDAY. AT THE SURFACE...A COLD FRONT WAS SITUATED FROM SOUTHWEST KANSAS INTO NORTHWEST MISSOURI. NORTH OF THIS FRONT COLD AIR HAD ADVECTED INTO NEBRASKA...WITH MID AFTERNOON TEMPERATURES GENERALLY IN THE 70S AND LOW 80S. DECENT LOW LEVEL MOISTURE DID REMAIN IN PLACE...AS DEWPOINTS ACROSS THE AREA WERE STILL IN THE UPPER 50S AND 60S. WITH THE MOISTURE IN PLACE AND STEEP LOW LEVEL LAPSE RATES...AN EXTENSIVE CUMULUS FIELD HAD DEVELOPED ACROSS WESTERN NEBRASKA. DESPITE DECENT SB INSTABILITY OF 1500-2500 J/KG WITH NO CAP...ANY SHOWERS AND THUNDERSTORMS HAVE HAD A PROBLEM MAINTAINING WITH NO ADDITIONAL FORCING IN PLACE. FOR THIS EVENING AND TONIGHT...ALTHOUGH THE HRRR IS INDICATING STORMS DEVELOPING OVER SOUTHWEST NEBRASKA AHEAD OF THE MAIN SYSTEM OVER THE ROCKIES...FEEL THIS ACTIVITY WILL BE WEAK WITH THE LACK OF FORCING FROM THE SHORTWAVE AND VERY LITTLE IF ANY FORCING COMING FROM ANY LOW LEVEL MOISTURE TRANSPORT. SO WILL FOCUS ON ACTIVITY MOVING OUT ONTO THE PLAINS WITH THE MAIN SHORTWAVE. AS THIS SHORTWAVE OVER WESTERN COLORADO MOVES EAST EXPECT FURTHER DEVELOPMENT OF CONVECTION ALONG THE FOOTHILLS AND INTO THE HIGH PLAINS. THE QUESTION WILL BE HOW FAR NORTH THE CONVECTION WILL DEVELOP. THE LATEST FEW RUNS OF THE HRRR INDICATE ACTIVITY DEVELOPING AS FAR NORTH AS SCOTTSBLUFF. THESE STORMS WOULD THEN MOVE SOUTHEAST ALONG A THETA-E GRADIENT. ALTHOUGH THERE IS SUFFICIENT INSTABILITY AND DEEP LAYER SHEAR WILL BE INCREASING...THE LOCAL AREA WILL BE ON THE NORTHERN FRINGE OF ANY ACTIVITY AND WITH THE BETTER FORCING OVER KANSAS EXPECT THE THREAT FOR ANY SEVERE STORMS TO STAY SOUTH OF THE AREA. FOR MONDAY THE SHORTWAVE TROUGH NOW OVER EASTERN IDAHO WILL MOVE ACROSS WYOMING AND THEN ACROSS NEBRASKA FROM NORTHWEST TO SOUTHEAST. NOT EXTREMELY CONFIDENT ON HOW MUCH COVERAGE OF SHOWERS AND THUNDERSTORMS THERE WILL BE AS THE AIRMASS WILL BE SLIGHTLY DRIER...WITH DEWPOINTS MAINLY IN THE 50S AND NO REAL SURGE OF DEEP MOISTURE ALOFT. AT THE PRESENT TIME THINK ANY CONVECTION WILL BE MORE ISOLATED TO SCATTERED IN NATURE. THE NEXT QUESTION IS WHERE THE CONVECTION WILL ACTUALLY BE. THE NAM SHOWS QPF ACROSS MUCH OF THE FORECAST AREA WHILE THE GFS/ECMWF ARE KEEPING IT MAINLY OVER THE PANHANDLE AND SOUTHWEST NEBRASKA. HAVE SIDED WITH THE GFS/ECMWF FOR TODAY AND HAVE LIMITED CHANCES FOR THE WESTERN AREAS. AS FOR HIGHS ON MONDAY...LOOKING FOR A SLIGHTLY COOLER DAY WITH HIGHS IN THE 70S AND LOW 80S AS COOLER AIR SLOWLY CONTINUES TO FILTER INTO THE AREA BEHIND THE UPPER LEVEL SYSTEM OVER SOUTHERN CANADA. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 341 PM CDT SUN JUN 22 2014 NORTHWEST FLOW ALOFT WILL PERSIST MONDAY NIGHT THROUGH TUESDAY NIGHT WITH THE PASSAGE OF TWO DISTINCT DISTURBANCES. MAINTAINED 30 POPS LATE MONDAY NIGHT ACROSS WESTERN ZONES...TO 40 POPS TUESDAY/TUESDAY NIGHT. PWAT VALUES FROM GFS INDICATE 120 TO NEAR 140 PERCENT OF NORMAL WITH DEEP LAYER SHEAR INCREASING TO 30 TO 40 KTS. THIS SUPPORTIVE OF STRONG THUNDERSTORMS TUESDAY AFTN/EVENING WITH LOCALLY HEAVY RAINFALL DUE TO SLOW STORM MOTION NEAR 10 KTS. SECOND DISTURBANCE FORECAST TO LIFT ACROSS LATE TUESDAY NIGHT AND WEDNESDAY WITH 40 POPS TUESDAY NIGHT...FOLLOWED BY 40 POPS FOR NCTRL WEDNESDAY. MAINLY 20 TO 30 POPS THURSDAY THROUGH SATURDAY. DUE TO WEAK RIDGING OVER THE REGION AND SWRLY FLOW TO OUR WEST WHICH MOVES IN BY FRIDAY NIGHT...MODEL AGREEMENT IN TIMING AND LOCATION IS RATHER POOR. TEMPERATURES HOWEVER WILL WARM FROM THE UPPER 70S TO LOWER 80S TUESDAY...MID 80S THURSDAY THROUGH SATURDAY TO AROUND 90 BY SUNDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 705 PM CDT SUN JUN 22 2014 FOR THE KLBF TERMINAL...THERE IS A THREAT FOR THUNDERSTORMS IN THE VICINITY OF THE KLBF TERMINAL THIS EVENING. SOME STORMS MAY IMPACT THE KLBF TERMINAL LATER THIS EVENING AS ACTIVITY MOVES INTO SWRN NEBRASKA. AT THIS TIME...CONFIDENCE IS LOW. OVERNIGHT INTO MONDAY...EXPECT MID AND HIGH CLOUDS TO PERSIST ACROSS THE KLBF TERMINAL WITH CIGS RANGING FROM 5000 TO 10000 FT AGL. FOR THE KVTN TERMINAL...EXPECT BROKEN MID LEVEL CLOUDINESS OVERNIGHT WITH CIGS AROUND 10000 FT AGL. CIGS WILL INCREASE TO 20000 FT AGL ON MONDAY. WINDS WILL BE LIGHT FROM THE NORTH AND NORTHWEST AT AROUND 10 KTS OVER THE NEXT 24 HRS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BROOKS LONG TERM...ROBERG AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
628 PM CDT SUN JUN 22 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 301 PM CDT SUN JUN 22 2014 THE PRIMARY SHORT TERM FORECAST CONCERN CENTERS AROUND THE CHANCE OF THUNDERSTORMS THIS AFTERNOON INTO TONIGHT. OVER THE LAST 8 HOURS HAVE GREATLY REDUCED THUNDERSTORM CHANCES FOR THIS AFTERNOON AND TONIGHT ACROSS OUR FORECAST AREA. THE GREATEST REDUCTION IN THUNDERSTORM CHANCES HAS BEEN ACROSS NEBRASKA. THERE IS MODEST TO EVEN FAIRLY GOOD INSTABILITY ACROSS THE FORECAST AREA ESPECIALLY ACROSS KANSAS...WITH LITTLE TO NO CIN. WIND SHEAR IS RATHER WEAK WITH DEEP LAYER 0-6 KM SHEAR OF LESS THAN 30 KTS. THE BIG ISSUE CENTERS AROUND FORCING OR THE LIFTING MECHANISM FOR ORGANIZED CONVECTION. FORCING MECHANISMS ACROSS THE REGION INCLUDE AN UPPER LEVEL SHORT WAVE TROUGH OVER IOWA...A SOUTHWARD SLIPPING SFC FRONTAL BOUNDARY ACROSS NORTHERN KANSAS...AND A VERY WEAK UPPER WAVE CENTERED OVER THE BLACK HILLS OF SOUTH DAKOTA EXTENDING INTO THE NEBRASKA PANHANDLE. THE SFC FRONT IS THE PRIMARY FORCING MECHANISM CURRENTLY LOCATED OVER OUR FORECAST AREA AND IT IS GRADUALLY SINKING SOUTH WHERE IT WILL EXIT OUR AREA BY LATER THIS EVENING. THEREFORE...THUNDERSTORMS SEEM MOST LIKELY LATE THIS AFTERNOON INTO EARLY THIS EVENING IN CLOSE PROXIMITY TO THE SFC FRONT OVER NORTHERN KANSAS AND THUS HAVE KEPT POPS AROUND 50/50 IN THESE SOUTHERN ZONES...WITH THE HIGHER POPS REALLY BEING SOUTH OF OUR FORECAST AREA TONIGHT. SOME FORECAST MODELS GENERATE CONVECTION ACROSS THE HIGH PLAINS TONIGHT IN ASSOCIATION WITH THE VERY WEAK UPPER WAVE...BUT 4 OUT OF 6 MODELS HAVE THIS PRECIPITATION DIEING OFF BEFORE REALLY REACHING OUR AREA TONIGHT. ONE OUTSIDE WRF RUN AND THE HRRR DO BRING CONVECTION FROM WESTERN PORTIONS OF NEBRASKA AND KANSAS INTO OUR FORECAST AREA LATE TONIGHT WHILE MOST MODELS DO NOT. WILL GO WITH THE MAJORITY GIVEN THERE IS NOT MUCH OF A LOW LEVEL JET TO HELP SUSTAIN CONVECTION TONIGHT ACROSS OUR FORECAST AREA. ANY THUNDERSTORMS THAT CAN FORM THIS AFTERNOON OR EVENING ACROSS KANSAS COULD BECOME SEVERE GIVEN THE HIGHER INSTABILITY ACROSS OUR SOUTHERN ZONES. MONDAY...MOST FORECAST MODELS INDICATE THAT WE WILL BE IN BETWEEN WEAK SHORT WAVE STORM SYSTEMS AND LIKELY DRY. TEMPERATURES WILL BE MILD WITH A LIGHT NORTHEAST WIND KEEPING THINGS A BIT COOLER THAN TODAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 301 PM CDT SUN JUN 22 2014 THE WEATHER PATTERN REMAINS UNSETTLED DURING THE EXTENDED PERIODS WITH INTERMITTENT CHANCES FOR THUNDERSTORMS. AN UPPER LOW PRESSURE SYSTEM WILL BE TRANSLATING SOUTHEAST FM CANADA TO THE UPPER MIDWEST REGION AT THE ONSET OF THE EXTENDED WITH THE FLOW ALOFT TRANSITIONING WEST NORTHWEST FOR A TIME AS ANOTHER TROUGH DIGS INTO THE PACIFIC NORTHWEST REGION. A SERIES OF WAVES EMBEDDED IN THE FLOW WILL AID IN TSTM DEVELOPMENT WITH TIMING/PLACEMENT DEPENDENT UPON WAVE TIMING AND BOUNDARY LOCATIONS AND BOUNDARY LOCATION WILL BE DEPENDENT UPON HOW CONVECTION UNFOLDS THE PREVIOUS DAY. IT IS DIFFICULT TO PINPOINT DETAILS ATTM AND WITH THE PROGRESSIVE PATTERN JUST CANNOT RULE OUT TSTM CHCS NEARLY EVERY DAY. CONVECTION MAY DEVELOP ALONG THE HIGH PLAINS AND ROLL EASTWARD...OR MAY INITIATE ALONG A BOUNDARY WITHIN THE AREA. SREF INSTABILITY PROGS INDICATE THE GREATER INSTABILITY MONDAY NIGHT WILL RESIDE ALONG THE HIGH PLAINS REGION...WHICH WILL BEGIN TO SPREAD EASTWARD ON TUESDAY...WITH MUCAPES INCREASING TO NEAR OR JUST ABOVE 1000 J/KG. WITH THE MORE MARGINAL INSTABILITY ON TUESDAY...NOT LOOKING FOR MUCH SEVERE WX JUST YET WITH INSTABILITY FURTHER INCREASING TUESDAY NIGHT INTO MID WEEK WITH RETURN FLOW...STRENGTHENING NOCTURNAL LLVL JET AND WAA/UPPER RIDGING AHEAD OF UPPER TROUGH IN THE PACIFIC NW. UPPER RIDGING SETTLES OVERHEAD FOR THE LATTER PART OF THE WORKWEEK AND MID LEVEL TEMPS INCREASE TO AROUND 14C SO CAP MAY LIMIT CONVECTION FOR A TIME. MODELS ARE NOT IN GREAT AGREEMENT ON THE TIMING/PROGRESSION OF THE WESTERN TROUGH AS IT PUSHES EAST THRU THE MOUNTAINS TOWARDS THE PLAINS AND WILL NEED TO MONITOR BUT CHCS FOR STORMS INCREASE AGAIN WITH THIS SYSTEM OVER THE WEEKEND OR EARLY NEXT WEEK. ALL BEING SAID...INTERMITTENT CHANCES FOR STORMS CONTINUE AND TEMPS LOOK FAIRLY SEASONAL ATTM. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 628 PM CDT SUN JUN 22 2014 VFR CONDITIONS TO CONTINUE THROUGH THE NEXT 24 HOURS. OCCASIONAL CLOUD COVER WITH A BASE NEAR 3000FT AGL...ALONG WITH ADDITIONAL CLOUD COVER NEAR 15000FT AGL...CAN BE EXPECTED THROUGH THE NEXT 24 HOURS. THE SURFACE WIND WILL REMAIN FROM THE NORTH FOR THE MOST PART DURING THE TAF PERIOD...SUSTAINED AT AROUND 08KTS. VISIBILITY RESTRICTION IS NOT EXPECTED THROUGH THE NEXT 24 HOURS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...WESELY LONG TERM...FAY AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
105 PM CDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1109 AM CDT SAT JUN 21 2014 FORECAST HAS BEEN UPDATED FOR PRECIPITATION TRENDS. STILL THINKING THE PRIMARY ACTIVITY WILL BE STORMS DEVELOPING ALONG THE MAIN SHORTWAVE TROUGH MOVING OUT OF THE ROCKIES WHICH WILL MOVE ACROSS NEBRASKA THIS EVENING AND OVERNIGHT. WHAT IS MORE OF A QUESTION IS IF THERE WILL BE ANY DEVELOPMENT AHEAD OF THE MAIN SHORTWAVE THIS AFTERNOON. THE HRRR HAS BEEN CONSISTENT SHOWING A MOISTURE BOUNDARY FROM ROUGHLY DEUEL COUNTY UP TO AROUND VALENTINE THIS AFTERNOON AS DRY AIR MIXES DOWN TO THE SURFACE BEHIND THE LINE AND MOISTURE CONTINUES TO SURGE NORTH AHEAD OF THE SURFACE LOW OVER COLORADO. HOWEVER...IT HAS BEEN BACK AND FORTH WITH DEVELOPING A FEW STORMS ON THIS BOUNDARY. UPPER LEVEL SUPPORT FROM THIS ISN/T GREAT BUT WITH THERE ARE MULTIPLE WEAK SHORTWAVES COMING OUT OF THE CENTRAL ROCKIES THAT WILL LIKELY BE OVER THE AREA EARLIER THIS AFTERNOON WHICH COULD BE JUST ENOUGH TO HELP STORMS DEVELOP AS THE CAP BREAKS. DID WANT TO AT LEAST HAVE A CHANCE FOR STORMS EARLIER IN THE AFTERNOON IN AREAS FURTHER EAST THAN WERE IN THE PREVIOUS FORECAST WITH THIS CONCERN. ALSO...EXPANDED THE WORDING FOR SEVERE STORMS POSSIBLE ACROSS ALL OF THE FORECAST AREA AS CONDITIONS WILL BE FAVORABLE ACROSS THE ENTIRE AREA FOR STORMS TO BECOME SEVERE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 346 AM CDT SAT JUN 21 2014 THE MCS ACROSS NORTHEAST COLORADO IS CLEARLY SHOWING CYCLONIC ROTATION ON RADAR AND IS TRACKING EAST NORTHEAST TOWARD SWRN NEB THIS MORNING. THE FORECAST TRACKS IT THROUGH SWRN NEB THIS MORNING AND ALLOWS FOR DECAY BY 14Z-15Z. THE RAP AND HRRR MODELS DO NOT HANDLE THIS FEATURE SO THE FORECAST IS HAND DRAWN FOR NOW WITH SCATTERED POPS BECOMING ISOLATED. AN ACTIVE SEVERE WEATHER DAY IS EXPECTED THIS AFTERNOON AND TONIGHT. THE MODEL CONSENSUS SUGGESTS STORMS WOULD FIRE ACROSS NORTHWEST NEBRASKA AROUND 21Z AND GROW UPSCALE EAST AND SOUTHEAST THROUGHOUT THE EVENING HOURS. THE MODELS ARE STRUGGLING WITH TEMPERATURES AND DEW POINTS. THE HRRR...GEMREG AND ECM SEEMED TO HAVE A BETTER HANDLE ON DEW POINTS AND DEVELOP VERY HIGH SFC BASED CAPE ACROSS WRN/NCNTL NEB. VALUES OF 3000-4000 J/KG DEVELOP WITH LITTLE OR NO CAP WHICH IS CONSISTENT WITH THE AFTN CONDITIONS LATELY. A STRONG MID LEVEL DISTURBANCE...CURRENTLY ACROSS NRN NEVADA WILL BE CROSSING THE CNTL/NRN PLAINS LATE THIS AFTN AND A PACIFIC COLD FRONT SWEEPS PART WAY THRU THE FCST AREA TONIGHT. THIS SETS UP A BROAD AND WEAKLY CAPPED WARM SECTOR COVERING MOST OF THE FCST AREA THIS AFTN. THE NAM AND RAP MODELS BACK THE SFC WINDS ACROSS NRN NEBRASKA THIS AFTN HEIGHTENING THE SEVERE WEATHER THREAT. IN GENERAL WINDS ALOFT ARE WEAK IN THE MODEL SOLNS BUT GIVEN THE STRENGTH OF THE UPPER LEVEL DISTURBANCE ACROSS THE WRN U.S. THE SHEAR COULD BE STRONGER TODAY THAN FRIDAY. THERE IS A BROAD SPREAD IN BULK SHEAR SHOWN IN THE MODELS AT 00Z THIS EVENING RANGING FROM LESS THAN 20 KT TO 35 KT AT BOTH NORTH PLATTE AND VALENTINE. USING THE HIGHER VALUES SUGGESTS POTENTIAL FOR SUPERCELL DEVELOPMENT AT BOTH LOCATIONS BUT THIS WOULD BE MORE LIKELY ACROSS THE WEST WITH THE SYSTEM EVOLVING INTO A QLMCS AS IT MOVES EAST INTO DEEPER MOISTURE ACROSS NCNTL NEB THIS EVENING. SPC REMAINS UNCERTAIN ON HOW THIS SYSTEM WILL EVOLVE SINCE THE MODELS SHOW A FULL SPECTRUM OF CONVECTIVE OPPORTUNITIES ACROSS THE BLACK HILLS AND THE NEBRASKA PANHANDLE TODAY. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 346 AM CDT SAT JUN 21 2014 12Z SUNDAY AND BEYOND. THE FOCUS OF EXTENDED PERIODS...AT LEAST INITIALLY...WILL BE ON THE TIMING AND LOCATION OF A FRONTAL BOUNDARY POISED TO CROSS WESTERN AND NORTH CENTRAL NEBRASKA SUNDAY. CONTRARY TO PREVIOUS MODEL RUNS...THE SOLUTIONS NOW SEEM TO KEEP THE FRONT MOVING THROUGH THE CWA FAIRLY PROGRESSIVELY...BUT THERE REMAINS CONSIDERABLE UNCERTAINTY ON HOW SUNDAY WILL PLAY OUT...ESPECIALLY SINCE A FAIRLY SIGNIFICANT MCS IS SHOWN TO DEVELOP SATURDAY NIGHT/EARLY SUNDAY ACROSS MUCH OF THE CENTRAL SANDHILLS AND PROJECT EAST OVERNIGHT. THUS CONFIDENCE IS SOMEWHAT LOWER THAN USUAL...BUT WHERE STORMS FIRE SUNDAY AFTERNOON...STEEP LAPSE RATES...A MODERATE TO STRONGLY UNSTABLE ATMOSPHERE AND SUFFICIENT SHEAR WOULD PROMOTE MULTI CELL UPDRAFTS CAPABLE OF LARGE HAIL AND GUSTY WIND. GIVEN THE CURRENT UNCERTAINTY...FELT THAT SUB 50 PERCENT POPS WERE ALL THAT WERE NEEDED BEFORE 00Z MONDAY. THEREAFTER...THERE IS SOME AGREEMENT IN THE SOLUTIONS THAT STORMS WILL FOCUS ACROSS OUR EASTERN AND SOUTHERN ZONES...FOR THIS AREA WILL MAINTAIN HIGH END CHANCE POPS...BUT NOT VENTURE INTO THE LIKELY REALM YET. THE GREATEST CHANGE MADE TO THE INHERITED FORECAST IS NOTED ON MONDAY AS THE SURFACE BOUNDARY IS NOW SHOWN TO BE WELL SOUTH AND EAST OF THE CWA...THUS POPS WERE LOWERED TO ACCOUNT FOR THIS NEW MODEL PROJECTION. WITHIN THE POST FRONTAL AIRMASS ON MONDAY AND TUESDAY...TEMPERATURES WILL BE PLEASANT...WITH HIGHS GENERALLY IN THE 70S FOR MOST LOCATIONS. NORTHWEST FLOW ALOFT DEVELOPS ACROSS THE HIGH PLAINS EARLY NEXT WEEK AS A NORTHERN PLAINS LOW DROPS SOUTH INTO THE EASTERN DAKOTAS...WITH RIDGING NOSING INTO THE CENTRAL ROCKIES. WEAK EASTERLY UPSLOPE FLOW WILL INTERACT WITH STRONG WARMING OFF THE HIGH PLAINS OF EASTERN COLORADO/WYOMING TO PROMOTE STORM DEVELOPMENT MONDAY AFTERNOON. A FEW OF THESE STORMS COULD DRIFT SOUTHEAST INTO WESTERN/SOUTHWEST PORTIONS OF THE CWA WITH A STRONG OR LOW END SEVERE STORM POSSIBLE. NORTHWEST FLOW CONTINUES TO DIRECT WEAK IMPULSES ACROSS THE HIGH PLAINS INTO CENTRAL SANDHILLS...ADDITIONAL STORM CHANCES WILL BE POSSIBLE THROUGH MID-WEEK. THEREAFTER...SUPPORT REMAINS FOR A DEEPENING TROUGH ACROSS THE WESTERN CONUS...WHICH WOULD PROMOTE SOUTHWEST FLOW ATOP THE CENTRAL PLAINS...SOUTHERLY SURFACE FLOW RETURNS. THE PATTEN MAY RETURN ACTIVE LATE WEEK AS ADDITIONAL ENERGY/EML IS DIRECTED NORTHEAST FROM THE WESTERN CONUS TROUGH TOWARD THE CENTRAL PLAINS. AFTER HIGHS IN THE 70S EARLY NEXT WEEK...TEMPERATURES GRADUALLY WARM INTO THE UPPER 80S TO LOWER 90S BY LATE...LOWS TO REMAIN SEASONAL THROUGH THE EXTENDED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 104 PM CDT SAT JUN 21 2014 VFR CONDITIONS EARLY THIS AFTERNOON ACROSS NEBRAKSA...BUT THUNDERSTORMS BECOME LIKELY FOR MUCH OF THE STATE THIS EVENING AND OVERNIGHT. THERE REMAINS CHANCES FOR ISOLATED TO SCATTERED COVERAGE OF STRONG THUNDERSTORMS LATE THIS AFTERNOON AHEAD OF THE MAIN WAVE OF STORMS THAT WILL MOVE ACROSS NEBRASKA TONIGHT. STORMS COULD BECOME STRONG...WITH STRONG WINDS AND HEAVY RAIN...AS WELL AS SOME LARGE HAIL IN THE STRONGEST STORMS. THERE SHOULD BE A BREAK FROM THE STORMS AND RAIN...WITH CONDITIONS IMPROVING TO VFR BY THE EARLY MORNING HOURS ON SUNDAY HOWEVER MORE SHOWERS AND STORMS ARE EXPECTED TO MOVE INTO THE AREA...ESPECIALLY OVER NORTHERN NEBRASKA BY 18Z SUNDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BROOKS SHORT TERM...CDC LONG TERM...JACOBS AVIATION...BROOKS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1109 AM CDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1109 AM CDT SAT JUN 21 2014 FORECAST HAS BEEN UPDATED FOR PRECIPITATION TRENDS. STILL THINKING THE PRIMARY ACTIVITY WILL BE STORMS DEVELOPING ALONG THE MAIN SHORTWAVE TROUGH MOVING OUT OF THE ROCKIES WHICH WILL MOVE ACROSS NEBRASKA THIS EVENING AND OVERNIGHT. WHAT IS MORE OF A QUESTION IS IF THERE WILL BE ANY DEVELOPMENT AHEAD OF THE MAIN SHORTWAVE THIS AFTERNOON. THE HRRR HAS BEEN CONSISTENT SHOWING A MOISTURE BOUNDARY FROM ROUGHLY DEUEL COUNTY UP TO AROUND VALENTINE THIS AFTERNOON AS DRY AIR MIXES DOWN TO THE SURFACE BEHIND THE LINE AND MOISTURE CONTINUES TO SURGE NORTH AHEAD OF THE SURFACE LOW OVER COLORADO. HOWEVER...IT HAS BEEN BACK AND FORTH WITH DEVELOPING A FEW STORMS ON THIS BOUNDARY. UPPER LEVEL SUPPORT FROM THIS ISN/T GREAT BUT WITH THERE ARE MULTIPLE WEAK SHORTWAVES COMING OUT OF THE CENTRAL ROCKIES THAT WILL LIKELY BE OVER THE AREA EARLIER THIS AFTERNOON WHICH COULD BE JUST ENOUGH TO HELP STORMS DEVELOP AS THE CAP BREAKS. DID WANT TO AT LEAST HAVE A CHANCE FOR STORMS EARLIER IN THE AFTERNOON IN AREAS FURTHER EAST THAN WERE IN THE PREVIOUS FORECAST WITH THIS CONCERN. ALSO...EXPANDED THE WORDING FOR SEVERE STORMS POSSIBLE ACROSS ALL OF THE FORECAST AREA AS CONDITIONS WILL BE FAVORABLE ACROSS THE ENTIRE AREA FOR STORMS TO BECOME SEVERE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 346 AM CDT SAT JUN 21 2014 THE MCS ACROSS NORTHEAST COLORADO IS CLEARLY SHOWING CYCLONIC ROTATION ON RADAR AND IS TRACKING EAST NORTHEAST TOWARD SWRN NEB THIS MORNING. THE FORECAST TRACKS IT THROUGH SWRN NEB THIS MORNING AND ALLOWS FOR DECAY BY 14Z-15Z. THE RAP AND HRRR MODELS DO NOT HANDLE THIS FEATURE SO THE FORECAST IS HAND DRAWN FOR NOW WITH SCATTERED POPS BECOMING ISOLATED. AN ACTIVE SEVERE WEATHER DAY IS EXPECTED THIS AFTERNOON AND TONIGHT. THE MODEL CONSENSUS SUGGESTS STORMS WOULD FIRE ACROSS NORTHWEST NEBRASKA AROUND 21Z AND GROW UPSCALE EAST AND SOUTHEAST THROUGHOUT THE EVENING HOURS. THE MODELS ARE STRUGGLING WITH TEMPERATURES AND DEW POINTS. THE HRRR...GEMREG AND ECM SEEMED TO HAVE A BETTER HANDLE ON DEW POINTS AND DEVELOP VERY HIGH SFC BASED CAPE ACROSS WRN/NCNTL NEB. VALUES OF 3000-4000 J/KG DEVELOP WITH LITTLE OR NO CAP WHICH IS CONSISTENT WITH THE AFTN CONDITIONS LATELY. A STRONG MID LEVEL DISTURBANCE...CURRENTLY ACROSS NRN NEVADA WILL BE CROSSING THE CNTL/NRN PLAINS LATE THIS AFTN AND A PACIFIC COLD FRONT SWEEPS PART WAY THRU THE FCST AREA TONIGHT. THIS SETS UP A BROAD AND WEAKLY CAPPED WARM SECTOR COVERING MOST OF THE FCST AREA THIS AFTN. THE NAM AND RAP MODELS BACK THE SFC WINDS ACROSS NRN NEBRASKA THIS AFTN HEIGHTENING THE SEVERE WEATHER THREAT. IN GENERAL WINDS ALOFT ARE WEAK IN THE MODEL SOLNS BUT GIVEN THE STRENGTH OF THE UPPER LEVEL DISTURBANCE ACROSS THE WRN U.S. THE SHEAR COULD BE STRONGER TODAY THAN FRIDAY. THERE IS A BROAD SPREAD IN BULK SHEAR SHOWN IN THE MODELS AT 00Z THIS EVENING RANGING FROM LESS THAN 20 KT TO 35 KT AT BOTH NORTH PLATTE AND VALENTINE. USING THE HIGHER VALUES SUGGESTS POTENTIAL FOR SUPERCELL DEVELOPMENT AT BOTH LOCATIONS BUT THIS WOULD BE MORE LIKELY ACROSS THE WEST WITH THE SYSTEM EVOLVING INTO A QLMCS AS IT MOVES EAST INTO DEEPER MOISTURE ACROSS NCNTL NEB THIS EVENING. SPC REMAINS UNCERTAIN ON HOW THIS SYSTEM WILL EVOLVE SINCE THE MODELS SHOW A FULL SPECTRUM OF CONVECTIVE OPPORTUNITIES ACROSS THE BLACK HILLS AND THE NEBRASKA PANHANDLE TODAY. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 346 AM CDT SAT JUN 21 2014 12Z SUNDAY AND BEYOND. THE FOCUS OF EXTENDED PERIODS...AT LEAST INITIALLY...WILL BE ON THE TIMING AND LOCATION OF A FRONTAL BOUNDARY POISED TO CROSS WESTERN AND NORTH CENTRAL NEBRASKA SUNDAY. CONTRARY TO PREVIOUS MODEL RUNS...THE SOLUTIONS NOW SEEM TO KEEP THE FRONT MOVING THROUGH THE CWA FAIRLY PROGRESSIVELY...BUT THERE REMAINS CONSIDERABLE UNCERTAINTY ON HOW SUNDAY WILL PLAY OUT...ESPECIALLY SINCE A FAIRLY SIGNIFICANT MCS IS SHOWN TO DEVELOP SATURDAY NIGHT/EARLY SUNDAY ACROSS MUCH OF THE CENTRAL SANDHILLS AND PROJECT EAST OVERNIGHT. THUS CONFIDENCE IS SOMEWHAT LOWER THAN USUAL...BUT WHERE STORMS FIRE SUNDAY AFTERNOON...STEEP LAPSE RATES...A MODERATE TO STRONGLY UNSTABLE ATMOSPHERE AND SUFFICIENT SHEAR WOULD PROMOTE MULTI CELL UPDRAFTS CAPABLE OF LARGE HAIL AND GUSTY WIND. GIVEN THE CURRENT UNCERTAINTY...FELT THAT SUB 50 PERCENT POPS WERE ALL THAT WERE NEEDED BEFORE 00Z MONDAY. THEREAFTER...THERE IS SOME AGREEMENT IN THE SOLUTIONS THAT STORMS WILL FOCUS ACROSS OUR EASTERN AND SOUTHERN ZONES...FOR THIS AREA WILL MAINTAIN HIGH END CHANCE POPS...BUT NOT VENTURE INTO THE LIKELY REALM YET. THE GREATEST CHANGE MADE TO THE INHERITED FORECAST IS NOTED ON MONDAY AS THE SURFACE BOUNDARY IS NOW SHOWN TO BE WELL SOUTH AND EAST OF THE CWA...THUS POPS WERE LOWERED TO ACCOUNT FOR THIS NEW MODEL PROJECTION. WITHIN THE POST FRONTAL AIRMASS ON MONDAY AND TUESDAY...TEMPERATURES WILL BE PLEASANT...WITH HIGHS GENERALLY IN THE 70S FOR MOST LOCATIONS. NORTHWEST FLOW ALOFT DEVELOPS ACROSS THE HIGH PLAINS EARLY NEXT WEEK AS A NORTHERN PLAINS LOW DROPS SOUTH INTO THE EASTERN DAKOTAS...WITH RIDGING NOSING INTO THE CENTRAL ROCKIES. WEAK EASTERLY UPSLOPE FLOW WILL INTERACT WITH STRONG WARMING OFF THE HIGH PLAINS OF EASTERN COLORADO/WYOMING TO PROMOTE STORM DEVELOPMENT MONDAY AFTERNOON. A FEW OF THESE STORMS COULD DRIFT SOUTHEAST INTO WESTERN/SOUTHWEST PORTIONS OF THE CWA WITH A STRONG OR LOW END SEVERE STORM POSSIBLE. NORTHWEST FLOW CONTINUES TO DIRECT WEAK IMPULSES ACROSS THE HIGH PLAINS INTO CENTRAL SANDHILLS...ADDITIONAL STORM CHANCES WILL BE POSSIBLE THROUGH MID-WEEK. THEREAFTER...SUPPORT REMAINS FOR A DEEPENING TROUGH ACROSS THE WESTERN CONUS...WHICH WOULD PROMOTE SOUTHWEST FLOW ATOP THE CENTRAL PLAINS...SOUTHERLY SURFACE FLOW RETURNS. THE PATTEN MAY RETURN ACTIVE LATE WEEK AS ADDITIONAL ENERGY/EML IS DIRECTED NORTHEAST FROM THE WESTERN CONUS TROUGH TOWARD THE CENTRAL PLAINS. AFTER HIGHS IN THE 70S EARLY NEXT WEEK...TEMPERATURES GRADUALLY WARM INTO THE UPPER 80S TO LOWER 90S BY LATE...LOWS TO REMAIN SEASONAL THROUGH THE EXTENDED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 623 AM CDT SAT JUN 21 2014 VFR IS EXPECTED ALL AREAS THROUGH 20Z. THEREAFTER SCATTERED STRONG TO SEVERE TSTMS ARE EXPECTED TO DEVELOP IN THE PANHANDLE WHICH WILL MOVE EAST AND BECOME NUMEROUS ACROSS NCNTL NEB BY 23Z-01Z. STORM ACTIVITY WILL PROGRESS EAST THROUGHOUT THE EVENING AND EXIT THE FCST AREA BY 06Z-12Z SUNDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BROOKS SHORT TERM...CDC LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
626 AM CDT SAT JUN 21 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 346 AM CDT SAT JUN 21 2014 THE MCS ACROSS NORTHEAST COLORADO IS CLEARLY SHOWING CYCLONIC ROTATION ON RADAR AND IS TRACKING EAST NORTHEAST TOWARD SWRN NEB THIS MORNING. THE FORECAST TRACKS IT THROUGH SWRN NEB THIS MORNING AND ALLOWS FOR DECAY BY 14Z-15Z. THE RAP AND HRRR MODELS DO NOT HANDLE THIS FEATURE SO THE FORECAST IS HAND DRAWN FOR NOW WITH SCATTERED POPS BECOMING ISOLATED. AN ACTIVE SEVERE WEATHER DAY IS EXPECTED THIS AFTERNOON AND TONIGHT. THE MODEL CONSENSUS SUGGESTS STORMS WOULD FIRE ACROSS NORTHWEST NEBRASKA AROUND 21Z AND GROW UPSCALE EAST AND SOUTHEAST THROUGHOUT THE EVENING HOURS. THE MODELS ARE STRUGGLING WITH TEMPERATURES AND DEW POINTS. THE HRRR...GEMREG AND ECM SEEMED TO HAVE A BETTER HANDLE ON DEW POINTS AND DEVELOP VERY HIGH SFC BASED CAPE ACROSS WRN/NCNTL NEB. VALUES OF 3000-4000 J/KG DEVELOP WITH LITTLE OR NO CAP WHICH IS CONSISTENT WITH THE AFTN CONDITIONS LATELY. A STRONG MID LEVEL DISTURBANCE...CURRENTLY ACROSS NRN NEVADA WILL BE CROSSING THE CNTL/NRN PLAINS LATE THIS AFTN AND A PACIFIC COLD FRONT SWEEPS PART WAY THRU THE FCST AREA TONIGHT. THIS SETS UP A BROAD AND WEAKLY CAPPED WARM SECTOR COVERING MOST OF THE FCST AREA THIS AFTN. THE NAM AND RAP MODELS BACK THE SFC WINDS ACROSS NRN NEBRASKA THIS AFTN HEIGHTENING THE SEVERE WEATHER THREAT. IN GENERAL WINDS ALOFT ARE WEAK IN THE MODEL SOLNS BUT GIVEN THE STRENGTH OF THE UPPER LEVEL DISTURBANCE ACROSS THE WRN U.S. THE SHEAR COULD BE STRONGER TODAY THAN FRIDAY. THERE IS A BROAD SPREAD IN BULK SHEAR SHOWN IN THE MODELS AT 00Z THIS EVENING RANGING FROM LESS THAN 20 KT TO 35 KT AT BOTH NORTH PLATTE AND VALENTINE. USING THE HIGHER VALUES SUGGESTS POTENTIAL FOR SUPERCELL DEVELOPMENT AT BOTH LOCATIONS BUT THIS WOULD BE MORE LIKELY ACROSS THE WEST WITH THE SYSTEM EVOLVING INTO A QLMCS AS IT MOVES EAST INTO DEEPER MOISTURE ACROSS NCNTL NEB THIS EVENING. SPC REMAINS UNCERTAIN ON HOW THIS SYSTEM WILL EVOLVE SINCE THE MODELS SHOW A FULL SPECTRUM OF CONVECTIVE OPPORTUNITIES ACROSS THE BLACK HILLS AND THE NEBRASKA PANHANDLE TODAY. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 346 AM CDT SAT JUN 21 2014 12Z SUNDAY AND BEYOND. THE FOCUS OF EXTENDED PERIODS...AT LEAST INITIALLY...WILL BE ON THE TIMING AND LOCATION OF A FRONTAL BOUNDARY POISED TO CROSS WESTERN AND NORTH CENTRAL NEBRASKA SUNDAY. CONTRARY TO PREVIOUS MODEL RUNS...THE SOLUTIONS NOW SEEM TO KEEP THE FRONT MOVING THROUGH THE CWA FAIRLY PROGRESSIVELY...BUT THERE REMAINS CONSIDERABLE UNCERTAINTY ON HOW SUNDAY WILL PLAY OUT...ESPECIALLY SINCE A FAIRLY SIGNIFICANT MCS IS SHOWN TO DEVELOP SATURDAY NIGHT/EARLY SUNDAY ACROSS MUCH OF THE CENTRAL SANDHILLS AND PROJECT EAST OVERNIGHT. THUS CONFIDENCE IS SOMEWHAT LOWER THAN USUAL...BUT WHERE STORMS FIRE SUNDAY AFTERNOON...STEEP LAPSE RATES...A MODERATE TO STRONGLY UNSTABLE ATMOSPHERE AND SUFFICIENT SHEAR WOULD PROMOTE MULTI CELL UPDRAFTS CAPABLE OF LARGE HAIL AND GUSTY WIND. GIVEN THE CURRENT UNCERTAINTY...FELT THAT SUB 50 PERCENT POPS WERE ALL THAT WERE NEEDED BEFORE 00Z MONDAY. THEREAFTER...THERE IS SOME AGREEMENT IN THE SOLUTIONS THAT STORMS WILL FOCUS ACROSS OUR EASTERN AND SOUTHERN ZONES...FOR THIS AREA WILL MAINTAIN HIGH END CHANCE POPS...BUT NOT VENTURE INTO THE LIKELY REALM YET. THE GREATEST CHANGE MADE TO THE INHERITED FORECAST IS NOTED ON MONDAY AS THE SURFACE BOUNDARY IS NOW SHOWN TO BE WELL SOUTH AND EAST OF THE CWA...THUS POPS WERE LOWERED TO ACCOUNT FOR THIS NEW MODEL PROJECTION. WITHIN THE POST FRONTAL AIRMASS ON MONDAY AND TUESDAY...TEMPERATURES WILL BE PLEASANT...WITH HIGHS GENERALLY IN THE 70S FOR MOST LOCATIONS. NORTHWEST FLOW ALOFT DEVELOPS ACROSS THE HIGH PLAINS EARLY NEXT WEEK AS A NORTHERN PLAINS LOW DROPS SOUTH INTO THE EASTERN DAKOTAS...WITH RIDGING NOSING INTO THE CENTRAL ROCKIES. WEAK EASTERLY UPSLOPE FLOW WILL INTERACT WITH STRONG WARMING OFF THE HIGH PLAINS OF EASTERN COLORADO/WYOMING TO PROMOTE STORM DEVELOPMENT MONDAY AFTERNOON. A FEW OF THESE STORMS COULD DRIFT SOUTHEAST INTO WESTERN/SOUTHWEST PORTIONS OF THE CWA WITH A STRONG OR LOW END SEVERE STORM POSSIBLE. NORTHWEST FLOW CONTINUES TO DIRECT WEAK IMPULSES ACROSS THE HIGH PLAINS INTO CENTRAL SANDHILLS...ADDITIONAL STORM CHANCES WILL BE POSSIBLE THROUGH MID-WEEK. THEREAFTER...SUPPORT REMAINS FOR A DEEPENING TROUGH ACROSS THE WESTERN CONUS...WHICH WOULD PROMOTE SOUTHWEST FLOW ATOP THE CENTRAL PLAINS...SOUTHERLY SURFACE FLOW RETURNS. THE PATTEN MAY RETURN ACTIVE LATE WEEK AS ADDITIONAL ENERGY/EML IS DIRECTED NORTHEAST FROM THE WESTERN CONUS TROUGH TOWARD THE CENTRAL PLAINS. AFTER HIGHS IN THE 70S EARLY NEXT WEEK...TEMPERATURES GRADUALLY WARM INTO THE UPPER 80S TO LOWER 90S BY LATE...LOWS TO REMAIN SEASONAL THROUGH THE EXTENDED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 623 AM CDT SAT JUN 21 2014 VFR IS EXPECTED ALL AREAS THROUGH 20Z. THEREAFTER SCATTERED STRONG TO SEVERE TSTMS ARE EXPECTED TO DEVELOP IN THE PANHANDLE WHICH WILL MOVE EAST AND BECOME NUMEROUS ACROSS NCNTL NEB BY 23Z-01Z. STORM ACTIVITY WILL PROGRESS EAST THROUGHOUT THE EVENING AND EXIT THE FCST AREA BY 06Z-12Z SUNDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
346 AM CDT SAT JUN 21 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 346 AM CDT SAT JUN 21 2014 THE MCS ACROSS NORTHEAST COLORADO IS CLEARLY SHOWING CYCLONIC ROTATION ON RADAR AND IS TRACKING EAST NORTHEAST TOWARD SWRN NEB THIS MORNING. THE FORECAST TRACKS IT THROUGH SWRN NEB THIS MORNING AND ALLOWS FOR DECAY BY 14Z-15Z. THE RAP AND HRRR MODELS DO NOT HANDLE THIS FEATURE SO THE FORECAST IS HAND DRAWN FOR NOW WITH SCATTERED POPS BECOMING ISOLATED. AN ACTIVE SEVERE WEATHER DAY IS EXPECTED THIS AFTERNOON AND TONIGHT. THE MODEL CONSENSUS SUGGESTS STORMS WOULD FIRE ACROSS NORTHWEST NEBRASKA AROUND 21Z AND GROW UPSCALE EAST AND SOUTHEAST THROUGHOUT THE EVENING HOURS. THE MODELS ARE STRUGGLING WITH TEMPERATURES AND DEW POINTS. THE HRRR...GEMREG AND ECM SEEMED TO HAVE A BETTER HANDLE ON DEW POINTS AND DEVELOP VERY HIGH SFC BASED CAPE ACROSS WRN/NCNTL NEB. VALUES OF 3000-4000 J/KG DEVELOP WITH LITTLE OR NO CAP WHICH IS CONSISTENT WITH THE AFTN CONDITIONS LATELY. A STRONG MID LEVEL DISTURBANCE...CURRENTLY ACROSS NRN NEVADA WILL BE CROSSING THE CNTL/NRN PLAINS LATE THIS AFTN AND A PACIFIC COLD FRONT SWEEPS PART WAY THRU THE FCST AREA TONIGHT. THIS SETS UP A BROAD AND WEAKLY CAPPED WARM SECTOR COVERING MOST OF THE FCST AREA THIS AFTN. THE NAM AND RAP MODELS BACK THE SFC WINDS ACROSS NRN NEBRASKA THIS AFTN HEIGHTENING THE SEVERE WEATHER THREAT. IN GENERAL WINDS ALOFT ARE WEAK IN THE MODEL SOLNS BUT GIVEN THE STRENGTH OF THE UPPER LEVEL DISTURBANCE ACROSS THE WRN U.S. THE SHEAR COULD BE STRONGER TODAY THAN FRIDAY. THERE IS A BROAD SPREAD IN BULK SHEAR SHOWN IN THE MODELS AT 00Z THIS EVENING RANGING FROM LESS THAN 20 KT TO 35 KT AT BOTH NORTH PLATTE AND VALENTINE. USING THE HIGHER VALUES SUGGESTS POTENTIAL FOR SUPERCELL DEVELOPMENT AT BOTH LOCATIONS BUT THIS WOULD BE MORE LIKELY ACROSS THE WEST WITH THE SYSTEM EVOLVING INTO A QLMCS AS IT MOVES EAST INTO DEEPER MOISTURE ACROSS NCNTL NEB THIS EVENING. SPC REMAINS UNCERTAIN ON HOW THIS SYSTEM WILL EVOLVE SINCE THE MODELS SHOW A FULL SPECTRUM OF CONVECTIVE OPPORTUNITIES ACROSS THE BLACK HILLS AND THE NEBRASKA PANHANDLE TODAY. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 346 AM CDT SAT JUN 21 2014 12Z SUNDAY AND BEYOND. THE FOCUS OF EXTENDED PERIODS...AT LEAST INITIALLY...WILL BE ON THE TIMING AND LOCATION OF A FRONTAL BOUNDARY POISED TO CROSS WESTERN AND NORTH CENTRAL NEBRASKA SUNDAY. CONTRARY TO PREVIOUS MODEL RUNS...THE SOLUTIONS NOW SEEM TO KEEP THE FRONT MOVING THROUGH THE CWA FAIRLY PROGRESSIVELY...BUT THERE REMAINS CONSIDERABLE UNCERTAINTY ON HOW SUNDAY WILL PLAY OUT...ESPECIALLY SINCE A FAIRLY SIGNIFICANT MCS IS SHOWN TO DEVELOP SATURDAY NIGHT/EARLY SUNDAY ACROSS MUCH OF THE CENTRAL SANDHILLS AND PROJECT EAST OVERNIGHT. THUS CONFIDENCE IS SOMEWHAT LOWER THAN USUAL...BUT WHERE STORMS FIRE SUNDAY AFTERNOON...STEEP LAPSE RATES...A MODERATE TO STRONGLY UNSTABLE ATMOSPHERE AND SUFFICIENT SHEAR WOULD PROMOTE MULTI CELL UPDRAFTS CAPABLE OF LARGE HAIL AND GUSTY WIND. GIVEN THE CURRENT UNCERTAINTY...FELT THAT SUB 50 PERCENT POPS WERE ALL THAT WERE NEEDED BEFORE 00Z MONDAY. THEREAFTER...THERE IS SOME AGREEMENT IN THE SOLUTIONS THAT STORMS WILL FOCUS ACROSS OUR EASTERN AND SOUTHERN ZONES...FOR THIS AREA WILL MAINTAIN HIGH END CHANCE POPS...BUT NOT VENTURE INTO THE LIKELY REALM YET. THE GREATEST CHANGE MADE TO THE INHERITED FORECAST IS NOTED ON MONDAY AS THE SURFACE BOUNDARY IS NOW SHOWN TO BE WELL SOUTH AND EAST OF THE CWA...THUS POPS WERE LOWERED TO ACCOUNT FOR THIS NEW MODEL PROJECTION. WITHIN THE POST FRONTAL AIRMASS ON MONDAY AND TUESDAY...TEMPERATURES WILL BE PLEASANT...WITH HIGHS GENERALLY IN THE 70S FOR MOST LOCATIONS. NORTHWEST FLOW ALOFT DEVELOPS ACROSS THE HIGH PLAINS EARLY NEXT WEEK AS A NORTHERN PLAINS LOW DROPS SOUTH INTO THE EASTERN DAKOTAS...WITH RIDGING NOSING INTO THE CENTRAL ROCKIES. WEAK EASTERLY UPSLOPE FLOW WILL INTERACT WITH STRONG WARMING OFF THE HIGH PLAINS OF EASTERN COLORADO/WYOMING TO PROMOTE STORM DEVELOPMENT MONDAY AFTERNOON. A FEW OF THESE STORMS COULD DRIFT SOUTHEAST INTO WESTERN/SOUTHWEST PORTIONS OF THE CWA WITH A STRONG OR LOW END SEVERE STORM POSSIBLE. NORTHWEST FLOW CONTINUES TO DIRECT WEAK IMPULSES ACROSS THE HIGH PLAINS INTO CENTRAL SANDHILLS...ADDITIONAL STORM CHANCES WILL BE POSSIBLE THROUGH MID-WEEK. THEREAFTER...SUPPORT REMAINS FOR A DEEPENING TROUGH ACROSS THE WESTERN CONUS...WHICH WOULD PROMOTE SOUTHWEST FLOW ATOP THE CENTRAL PLAINS...SOUTHERLY SURFACE FLOW RETURNS. THE PATTEN MAY RETURN ACTIVE LATE WEEK AS ADDITIONAL ENERGY/EML IS DIRECTED NORTHEAST FROM THE WESTERN CONUS TROUGH TOWARD THE CENTRAL PLAINS. AFTER HIGHS IN THE 70S EARLY NEXT WEEK...TEMPERATURES GRADUALLY WARM INTO THE UPPER 80S TO LOWER 90S BY LATE...LOWS TO REMAIN SEASONAL THROUGH THE EXTENDED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1212 AM CDT SAT JUN 21 2014 THE THUNDERSTORM COMPLEX IN CENTRAL AND SOUTHWEST NEBRASKA IS EXPECTED TO MOVE INTO EASTERN NEBRASKA BY 07Z. SHORT RANGE PROJECTIONS INDICATE THAT ANOTHER SMALL SYSTEM MAY DEVELOP IN WYOMING AND MOVE ACROSS SOUTHWEST NEBRASKA. HOWEVER...RAIN-COOLED AIR FROM THE STORM SYSTEM THAT JUST WENT THROUGH HAS PROBABLY STABILIZED THE ATMOSPHERE ENOUGH THAT IT IS UNLIKELY. THUNDERSTORMS ARE AGAIN EXPECTED SATURDAY AFTERNOON...STARTING WEST OF VTN-LBF 18-21Z AND SPREADING TO ANW-BBW 21-24Z. COVERAGE IS STILL EXPECTED TO BE LESS THAN 40 PERCENT...SO THEY WILL NOT BE INCLUDED IN THE TERMINAL FORECASTS FOR VTN OR LBF. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...JACOBS AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT SAT JUN 21 2014 .SYNOPSIS...AN UPPER DISTURBANCE WILL MOVE SOUTHEAST ACROSS THE AREA TODAY. A WEAK COLD FRONT WILL PUSH SOUTHEAST THROUGH CENTRAL NORTH CAROLINA TONIGHT...USHERING IN SLIGHTLY COOLER AND DRIER WEATHER FOR SUNDAY AND MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 310 AM SATURDAY... RADAR SHOWS A FAIRLY WELL DEFINED MCV MOVING ALONG THE NC/VA BORDER NORTH OF KIXA...WITH AND OUTFLOW BOUNDARY EXTENDING THROUGH THE COASTAL PLAIN TO THE SOUTHERN PIEDMONT. THE ASSOCIATED SHOWERS AND STORMS ARE NOW MOSTLY EAST OF THE CWA. SUBSIDENCE BEHIND THE MCV SHOULD KEEP ANY ADDITIONAL SHOWERS VERY ISOLATED THIS MORNING...WHILE ATTENTION TURNS TO A SHORTWAVE UPSTREAM OVER EASTERN TN/KY...WHICH IS PROGGED TO CROSS THE CWA BETWEEN 15Z AND 21Z. WITH THE COLD FRONT OVER VA SINKING SOUTH AND A WEAK WAVE OF LOW PRESSURE ASSOCIATED WITH THE SHORTWAVE SETTLED ACROSS THE AREA THIS AFTERNOON...LOW-LEVEL CONVERGENCE...ALBEIT WEAK...WILL BE FOCUS OVER NC. THE TIMING OF THE SHORTWAVE SHOULD CAUSE SCATTERED SHOWERS AND STORMS OVER THE WESTERN PIEDMONT TO BECOME MORE NUMEROUS EAST OF ROUGHLY US HWY 1 BY EARLY AFTERNOON AS IT ENCOUNTERS PEAK HEATING AND MLCAPE OVER 1000 J/KG. THE SEVERE THREAT APPEARS TO BE LIMITED GIVEN WEAK WIND FIELDS AND ONLY MARGINAL INSTABILITY...BUT WITH PW OF UP TO 2 INCHES...RAIN WILL BE HEAVY AND THE SHORTWAVE MAY LOCALLY ENHANCE THE THREAT OF DAMAGING WINDS IF A FEW STORMS CAN CONGEAL INTO A LARGER CLUSTER. HIGHS IN THE UPPER 80S NORTH TO LOWER 90S SOUTH. TONIGHT... EXPECTED SHOWERS AND STORMS TO LARGELY COME TO AN END BEHIND THE PASSING SHORTWAVE BY 03Z. IN ITS WAKE...THE AFOREMENTIONED COLD FRONT WILL FINALLY SURGE SOUTH THROUGH THE AREA...WHICH MAY TRIGGER A FEW ADDITIONAL SHOWERS. WILL END CHANCE POPS AFTER MIDNIGHT WITH JUST A SLIGHT CHANCE THEREAFTER. LOWS IN THE MID 60S NORTH TO LOWER 70S SOUTH. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... AS OF 310 AM SATURDAY... THE COLD FRONT WILL SLIP SOUTH OVER SC ON SUNDAY AS HIGH PRESSURE BUILDS OVER THE MID-ATLANTIC STATES AND PW DROPS BACK TOWARD NORMAL. LOW-LEVEL CONVERGENCE AND THE AXIS OF BEST INSTABILITY WILL ACCORDINGLY BE SOUTH OF THE CWA...WITH JUST A SLIGHT CHANCE OF A SHOWER OR STORM FROM THE SOUTHERN PIEDMONT TO THE SOUTHERN COASTAL PLAIN. LOW-LEVEL THICKNESSES DROP BACK SLIGHTLY BELOW NORMAL TO AROUND 1395...WHICH SUGGESTS HIGHS IN THE MID TO UPPER 80S. RETURN FLOW WILL BEGIN TO DEVELOP SUNDAY NIGHT INTO MONDAY..THOUGH MODELS LOOK A BIT TOO AGGRESSIVE WITH STRATUS OVER THE WESTERN PIEDMONT MONDAY MORNING. LOWS IN THE MID TO UPPER 60S. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 230 AM SATURDAY... CYCLE TOWARDS A WARMER...MOISTER...AND MORE ACTIVE AIRMASS CONTINUES THROUGH THE WEEK AS SURFACE HIGH PRESSURE RETREATS AND LOW LEVEL FLOW VEERS EAST TO SOUTHEAST MONDAY AND TUESDAY. INITIALLY...THE AIRMASS WILL BE ONLY MODESTLY UNSTABLE MONDAY WITH WEAK LOW LEVEL FORCING AND SHORT WAVE RIDGING ALOFT. THIS SHOULD WILL LIMIT CONVECTION TO THE FAR WEST...WITH ONLY A SLIGHT CHANCE FOR A FEW STORMS TO MIGRATE INTO THE PIEDMONT. HIGHS MONDAY WILL BE SEASONABLE...FROM 85 TO 90. LEE SURFACE TROF RE-DEVELOPS AND PRECIPITABLE WATER INCREASES TO NEAR 2 INCHES BY TUESDAY AFTERNOON AND DIURNAL CONVECTION WILL BE MORE WIDESPREAD...POTENTIALLY LINGERING OVERNIGHT AS A SHORTWAVE APPROACHES FROM THE WEST. HIGHS TUESDAY WILL REACH THE UPPER 80S TO LOWER 90S. POTENTIAL FOR AT LEAST SCATTERED CONVECTION WILL LINGER WEDNESDAY THROUGH FRIDAY IN THE DEEPLY MOIST AIRMASS WITH HIGHS REACHING THE LOWER 90S AFTER MORNING MINS WITHIN A FEW DEGREES RIGHT OR LEFT OF 70. MID LEVEL FLOW WILL BE NEAR-ZONAL WITH LOW AMPLITUDE TROFFING OVER THE GREAT LAKES PROVIDING FAVORABLE STEERING FLOW FOR UPSTREAM DISTURBANCES TO ENHANCE COVERAGE AND ORGANIZATION OF EXPECTED CONVECTION. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 140 AM SATURDAY... A BROKEN LINE OF SHOWERS AND STORMS IS NOW MOSTLY EAST OF ALL TAF SITES..THOUGH A FEW SHOWERS STILL INGER TO THE WEST-NORTHWEST OF KFAY AND MAY STILL IMPACT THE TERMINAL THROUGH 07Z. AREAS OF LOW CLOUDS AND REDUCED VSBY WILL CONTINUE THROUGH THE REMAINDER OF THE NIGHT...PARTICULARLY WHERE MORE RAIN FEEL. CURRENT THINKING IS THAT VSBYS WILL REMAIN MOSTLY MVFR KRDU/KRWI/KFAY....WITH A BETTER CHANCE OF VSBYS DROPPING TO IFR OR LIFR AT KRWI. THE HRRR MODEL ALSO SHOWS SOME STRATUS DEVELOPING JUST TO THE WEST OF KFAY BY 09Z...SO THIS WILL BE MONITORED. TODAY... STRONG HEATING ALONG WITH AN UPPER DISTURBANCE AND WEAK COLD FRONT WILL LEAD TO SCATTERED TO NUMEROUS SHOWERS AND STORMS...AS EARLY AS 15Z AT KINT/KGSO AND MORE LIKELY AFTER 18Z AT KRDU/KFAY/KRWI (WHERE CONFIDENCE IS HIGHEST). A FEW STORMS MAY BE STRONG TO SEVERE. ONCE THE STORMS MOVE EAST OF CENTRAL NC DURING THE EVENING HOURS...WINDS WILL BECOME MORE NORTH-NORTHEASTERLY BEHIND THE COLD FRONT AS IT SETTLES SOUTH INTO SC. OUTLOOK... THERE WILL BE SLIGHT CHANCES FOR DIURNAL CONVECTION THROUGH THE WEEKEND AND THE BEGINNING OF NEXT WEEK. CHANCES INCREASE ON TUESDAY AND WEDNESDAY AFTERNOONS WITH A GREATER THREAT FOR SUB- VFR CONDITIONS. THERE WILL BE ALSO CHANCES FOR EARLY MORNING FOG/STRATUS TUESDAY AND WEDNESDAY MORNINGS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MLM NEAR TERM...BLS SHORT TERM...BLS LONG TERM...MLM AVIATION...BLS/ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
140 AM EDT SAT JUN 21 2014 .SYNOPSIS... WITH A WARM AND UNSTABLE AIR MASS IN PLACE... A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK SOUTHEAST ACROSS THE REGION TODAY. A COLD FRONT WILL PUSH SOUTHEAST THROUGH CENTRAL NORTH CAROLINA TONIGHT. && .NEAR TERM /THROUGH SATURDAY NIGHT/... AS OF 1010 PM FRIDAY... TONIGHT: AN MCV NEAR THE VA CAMPBELL/CHARLOTTE COUNTY LINE...AND A TRAILING ONE NEAR THE WV/VA BORDER...WILL TRACK ESE TO THE EASTERN VA-NE NC COAST BY EARLY SAT. THE LEAD MCV HAS SUPPORTED THE MAINTENANCE OF A RECENTLY STRENGTHENING CLUSTER OF STORMS IN A LOOSELY-ORGANIZED ARC FROM THE CENTRAL-SOUTHERN VA PIEDMONT SOUTHWARD TO NEAR KHNZ THEN SOUTHWESTWARD TO KEXX. THE ASSOCIATED STORMS/SFC COLD POOLS EASTWARD MOVEMENT WILL MAINTAIN ENHANCED STORM RELATIVE FLOW/CONVERGENCE...OWING TO AN EASTERLY SFC FLOW COMPONENT TO THE NORTH OF THE LEAD SFC FRONT OVER SOUTHERN NC...AND SHOULD CONSEQUENTLY MAINTAIN THE STORM CLUSTER AS IT MARCHES EAST ACROSS THE FAR NE PIEDMONT AND NORTHERN COASTAL PLAIN DURING THE NEXT COUPLE OF HOURS. THOUGH THESE STORMS ARE NOT TERRIBLY REFLECTIVE AS A RESULT OF ONLY MARGINAL MLCAPE OF 1500 J/KG OR LESS DUE TO WEAK MID LEVEL LAPSE RATES AND NOCTURNAL COOLING...00Z-OBSERVED PRECIPITABLE WATER VALUES OF AROUND 1.75 INCHES AT BOTH KGSO AND KMHX...IN CONJUNCTION WITH THE STRONG CONVERGENCE/FAVORABLE STORM RELATIVE FLOW ORIENTED PERPENDICULAR TO THE STORM CLUSTER/COLD POOL BOUNDARY...HAS RESULTED IN RELATIVELY DEEP AND WIDE PRECIPITATION CORES SUPPORTIVE OF STRONG TO EVEN MARGINALLY SEVERE DOWNDRAFTS... AND HEAVY RAIN. WEAK CINH AND LINGERING INSTABILITY WILL SUPPORT ISOLATED TO WIDELY SCATTERED STORMS ELSEWHERE ACROSS CENTRAL NC TONIGHT...WITH THE BEST COVERAGE WITH THE AFOREMENTIONED ONGOING CLUSTER NEAR THE VA BORDER...WHERE MCV-RELATED FORCING WILL BE RELATIVELY MAXIMIZED. PREVIOUSLY FORECAST LOWS 68-73. -MWS FOR SAT/SAT NIGHT: NOCTURNAL CONVECTION IN THE NORTHEAST CWA SHOULD BE EXITING THE CWA NEAR OR SOON AFTER DAYBREAK... FOLLOWED BY A PERIOD OF RELATIVE SUBSIDENCE THROUGH THE REST OF THE MORNING... AGAIN FOLLOWING THE TRENDS OF THE HIGH-RES WRF-NMM AND WRF-ARW. THEN... THE PRESENCE OF THE OLD MCV ACROSS SRN AND ERN NC ALONG WITH GOOD HEATING THROUGH THE FIRST PART OF THE DAY SHOULD HELP FUEL SCATTERED TO NUMEROUS SHOWERS AND STORMS. WE COULD SEE A COMBINATION OF MOUNTAIN CONVECTION PUSHING TO THE ESE THROUGH CENTRAL NC DURING THE AFTERNOON... IN ADDITION TO STORMS FORMING OVER THE ERN PIEDMONT/SANDHILLS/COASTAL PLAIN WHERE DEWPOINTS SHOULD BE HIGHEST WITH THE LONGEST PERIOD OF HEATING... AND ALONG AND AHEAD OF A SURFACE LOW OVER CENTRAL NC. HIGHER TEMPS/DEWPOINTS HERE WILL POTENTIALLY PUSH MUCAPE UP TO 1500-2500 J/KG... ALBEIT WITH CONTINUED WEAK DEEP LAYER SHEAR OF JUST AROUND 20 KTS. PW VALUES IN THE EAST ARE ALSO EXPECTED TO PEAK OVER 2 INCHES BY LATE IN THE DAY... FAVORING GOOD STORM COVERAGE AND POTENTIAL HEAVY RAIN WITH SLOW MOVING CELLS. THIS ALL BOILS DOWN TO HIGH PRECIP CHANCES (60- 70%) OVER ALL OF CENTRAL NC SAT AFTERNOON INTO THE EVENING. COOL SURFACE HIGH PRESSURE WELL TO OUR NNW WILL PUSH THE LOW AND FRONT TO OUR SE SAT NIGHT... CAUSING A WIND SHIFT TO NORTH THEN NE LATE... BRINGING AN END TO PRECIP CHANCES FROM NW TO SE. WE SHOULD SEE FORMATION OF LOW CLOUDS POST-FRONT OVER THE EASTERN HALF OF THE CWA WITHIN THE NNE FLOW. HIGHS 85-94 FROM NNE TO SW. LOWS 65 NORTH TO 72 SOUTH. -GIH && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 230 PM FRIDAY... SURFACE LOW PRESSURE WILL BE MOVING OFFSHORE TO BEGIN THE DAY ON SUNDAY...WITH HIGH PRESSURE GRADUALLY BUILDING EAST AND DOWN THE EAST COAST THROUGH MONDAY. THIS WILL PUSH A FRONT FURTHER SOUTH OF THE FORECAST AREA...LIKELY INTO SC/GA. IN ADDITION...SHORTWAVE RIDGING WILL ALSO BUILD EAST OVER THE REGION. THEREFORE...THIS TIME FRAME OF ENTIRE FORECAST PERIOD IS WHEN PRECIP CHANCES WILL BE THE LOWEST... ALTHOUGH NON-ZERO. SUNDAY SHOULD BE THE DRIEST DAY (WITH ONLY A FEW ISOLATED STORMS EXPECTED)...THEN MAYBE SOME HIGHER CHANCES ACROSS THE WEST ON MONDAY AS THE HIGH STARTS TO PULL AWAY AND MOISTURE BEGINS TO INCREASE ON THE BACK SIDE OF THE DEPARTING HIGH. TEMPS WILL BE A SEVERAL DEGREES LOWER THAN PREVIOUS DAYS BEHIND THE FRONT...WITH HIGHS EXPECTED TO BE IN THE MID/UPPER 80S TO NEAR 90 DEGREES AND OVERNIGHT LOWS IN THE MID/UPPER 60S TO NEAR 70 DEGREES. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 230 PM FRIDAY... PRECIP CHANCES...MOSTLY DIURNAL IN NATURE...WILL BEGIN TO INCREASE ON TUESDAY AND THEN PERSIST FOR THE REMAINDER OF THE WEEK AS MOISTURE INCREASES WITHIN THE RETURN FLOW THAT SETS UP ON THE BACKSIDE OF THE DEPARTING HIGH. IN ADDITION...FLOW ALOFT WILL BECOME SOUTHWESTERLY (THUS INCREASING DEEP LAYER MOISTURE) AS LARGE SCALE TROUGHING MOVES OVER THE GREAT LAKES AND MS RIVER VALLEY. ADDITIONALLY...TEMPS WILL CLIMB A FEW DEGREES...WITH HIGHS GENERALLY IN THE UPPER 80S TO LOWER 90S AND OVERNIGHT LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 140 AM SATURDAY... A BROKEN LINE OF SHOWERS AND STORMS IS NOW MOSTLY EAST OF ALL TAF SITES..THOUGH A FEW SHOWERS STILL INGER TO THE WEST-NORTHWEST OF KFAY AND MAY STILL IMPACT THE TERMINAL THROUGH 07Z. AREAS OF LOW CLOUDS AND REDUCED VSBY WILL CONTINUE THROUGH THE REMAINDER OF THE NIGHT...PARTICULARLY WHERE MORE RAIN FEEL. CURRENT THINKING IS THAT VSBYS WILL REMAIN MOSTLY MVFR KRDU/KRWI/KFAY....WITH A BETTER CHANCE OF VSBYS DROPPING TO IFR OR LIFR AT KRWI. THE HRRR MODEL ALSO SHOWS SOME STRATUS DEVELOPING JUST TO THE WEST OF KFAY BY 09Z...SO THIS WILL BE MONITORED. TODAY... STRONG HEATING ALONG WITH AN UPPER DISTURBANCE AND WEAK COLD FRONT WILL LEAD TO SCATTERED TO NUMEROUS SHOWERS AND STORMS...AS EARLY AS 15Z AT KINT/KGSO AND MORE LIKELY AFTER 18Z AT KRDU/KFAY/KRWI (WHERE CONFIDENCE IS HIGHEST). A FEW STORMS MAY BE STRONG TO SEVERE. ONCE THE STORMS MOVE EAST OF CENTRAL NC DURING THE EVENING HOURS...WINDS WILL BECOME MORE NORTH-NORTHEASTERLY BEHIND THE COLD FRONT AS IT SETTLES SOUTH INTO SC. OUTLOOK... THERE WILL BE SLIGHT CHANCES FOR DIURNAL CONVECTION THROUGH THE WEEKEND AND THE BEGINNING OF NEXT WEEK. CHANCES INCREASE ON TUESDAY AND WEDNESDAY AFTERNOONS WITH A GREATER THREAT FOR SUB- VFR CONDITIONS. THERE WILL BE ALSO CHANCES FOR EARLY MORNING FOG/STRATUS TUESDAY AND WEDNESDAY MORNINGS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...MWS/HARTFIELD SHORT TERM...KRD LONG TERM...KRD AVIATION...BLS/ELLIS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1250 PM CDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1230 PM CDT SAT JUN 21 2014 CURRENT SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY HAS WORKED ITS WAY INTO FAR WRN ND...WHILE MOISTURE CONTINUES TO PUSH ITS WAY INTO CTRL/ERN ND. HAVE DECIDED TO PUSH OUT A FLASH FLOOD WATCH OVER PTNS OF S CTRL ND INTO THE JAMES RIVER VALLEY GIVEN PLENTY OF MOISTURE ON HAND FOR STORMS TO WORK WITH COMBINED WITH WET SOILS. LATEST GUIDANCE SUGGESTS STORMS SHOULD NOT BE STATIONARY...BUT TRAINING WILL BE POSSIBLE ALONG WITH SOME STORMS BEING PROLIFIC RAIN PRODUCERS. ALONG WITH THE FLOOD THREAT...STILL HAVE THE HAIL/WIND THREAT OVER SIMILAR AREAS AS GUIDANCE STILL SHOWS GOOD INSTABILITY/SHEAR. UPDATES HAVE BEEN SENT. UPDATE ISSUED AT 926 AM CDT SAT JUN 21 2014 CURRENT SURFACE ANALYSIS PLACES FRONTAL BOUNDARY PUSHING THROUGH ERN MT WHILE MOISTURE CONTINUES TO SLOWLY ADVECT TOWARDS S CTRL ND. UPPER LEVEL ANALYSIS CONTINUES TO SHOW W/SWRLY FLOW WITH A VARIETY OF WEAK WAVES MOVING THROUGH. MAIN CONCERN FOR MORNING FORECAST IS SEVERE THREAT MAINLY OVER S CTRL INTO SERN ND. MORNING GUIDANCE CONTINUES TO SHOW THE STRONGEST INSTABILITY MAINLY SOUTH/EAST OF THE CWA...THOUGH STRONG ENOUGH INTO OUR AREA TO BRING SEVERE CONCERNS. SHEAR INCREASES THROUGH THE AFTERNOON (~40KTS 0-6KM BULK) AND WILL BE AMPLE FOR SUPERCELL DEVELOPMENT BY AFTERNOON. LATEST GUIDANCE SUGGESTS MOST STORMS SHOULD FORM MAINLY IN THE JAMES RIVER VALLEY REGION...THOUGH SOME CONCERN STILL EXITS A BIT TOWARDS THE WEST. MORNING UPDATE WILL ADDRESS SEVERE CONCERNS LATER TODAY AND HAVE ADJUSTED POPS WITH MORNING GUIDANCE. UPDATES WILL BE OUT SHORTLY. UPDATE ISSUED AT 626 AM CDT SAT JUN 21 2014 WEAK CONVECTION ONGOING ACROSS THE SOUTHWEST. DECIDED TO REMOVE THUNDER FROM FORECAST FOR THE MORNING. OTHERWISE THIS BATCH OF SHOWERS WILL TRACK THROUGH SOUTH CENTRAL NORTH DAKOTA. LATE THIS AFTERNOON STRONGER STORMS WILL FORM ACROSS SOUTH CENTRAL NORTH DAKOTA AS THE COLD FRONT PROGRESSES EAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CDT SAT JUN 21 2014 LATEST SEVERAL HRRR RUNS HAVE INSISTED THAT SHOWER ACTIVITY OVER FAR EASTERN MONTANA WILL HOLD TOGETHER...EVEN EXPANDING AND STRENGTHENING...WILL SLIDE EASTWARD THIS MORNING AND THEN DISSIPATE OVER SOUTHEASTERN NORTH DAKOTA. IT SEEMS REASONABLE BASED ON THE PAST FEW HOURS OF SATELLITE AND RADAR INTERROGATION. THE MORE PRESSING CONCERN IS FOR POSSIBLE SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING SOUTH OF INTERSTATE 94. SPC SLID THEIR CONVECTIVE OUTLOOK SLIGHT RISK TO THE NORTH THIS MORNING. ML CAPE IS EXPECTED TO BE IN THE 1500 J/KG BALLPARK...AND SHEAR WILL BE SUPPORTIVE OF SUPERCELLS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 327 AM CDT SAT JUN 21 2014 THE EXTENDED PERIOD WILL BE MODERATELY ACTIVE FOR THIS TIME OF THE YEAR WITH TWO FEATURES BRINGING PRECIPITATION TO THE REGION. FIRST THE REMNANTS OF THE UPPER LOW ACROSS SASK/MANT WILL SWING SOUTH THROUGH THE NORTHERN PLAINS MONDAY AND TUESDAY BRINGING SCATTERED SHOWERS/THUNDERSTORMS TO THE REGION. SUFFICIENT INSTABILITY EXISTS FOR ROUTINE THUNDERSTORMS WITH NOTHING SCREAMING SEVERE POTENTIAL AT THIS TIME. A CHANGE TO COOLER WEATHER ALSO IS ANTICIPATED AS THIS LOW WILL BRING COOLER H850 TEMPS WITH IT. FOLLOWING THIS THE ECMWF/GFS BOTH ARE BRINGING EASTERN PACIFIC SHORTWAVE ENERGY INTO WESTERN NORTH AMERICA AND ARE CARVING OUT A LONGWAVE TROUGH ACROSS THE WESTERN US. THE EUROPEAN SEEMS TO BE MORE AGGRESSIVE WITH A FASTER AND DEEPER TROUGH. EITHER WAY THE RESULT WILL BE A SOUTHWEST FLOW ALOFT...WITH AN OPENING TO GULF MOISTURE AND EVENTUALLY A MORE ACTIVE THUNDERSTORM PATTERN FOR THE LAST WEEK OF JUNE. USING ALLBLEND GUIDANCE RESULTS IN A CHANCE OF THUNDERSTORMS WEDNESDAY TROUGH FRIDAY WITH NORMAL TO ABOVE NORMAL TEMPERATURES RETURNING BY THE END OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 626 AM CDT SAT JUN 21 2014 AN AREA OF SHOWERS SHOULD MOVE EASTWARD FROM KDIK TO KBIS AND KJMS. ANOTHER ROUND OF STRONGER THUNDERSTORMS SHOULD FORM AROUND 21Z NEAR KBIS/KJMS. KISN/KMOT SHOULD REMAIN DRY AND VFR. && .BIS WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH LATE TONIGHT FOR NDZ023-025-036-037-046>048-050-051. && $$ UPDATE...JJS SHORT TERM...SCHECK LONG TERM...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
936 AM CDT SAT JUN 21 2014 .UPDATE... ISSUED AT 926 AM CDT SAT JUN 21 2014 CURRENT SURFACE ANALYSIS PLACES FRONTAL BOUNDARY PUSHING THROUGH ERN MT WHILE MOISTURE CONTINUES TO SLOWLY ADVECT TOWARDS S CTRL ND. UPPER LEVEL ANALYSIS CONTINUES TO SHOW W/SWRLY FLOW WITH A VARIETY OF WEAK WAVES MOVING THROUGH. MAIN CONCERN FOR MORNING FORECAST IS SEVERE THREAT MAINLY OVER S CTRL INTO SERN ND. MORNING GUIDANCE CONTINUES TO SHOW THE STRONGEST INSTABILITY MAINLY SOUTH/EAST OF THE CWA...THOUGH STRONG ENOUGH INTO OUR AREA TO BRING SEVERE CONCERNS. SHEAR INCREASES THROUGH THE AFTERNOON (~40KTS 0-6KM BULK) AND WILL BE AMPLE FOR SUPERCELL DEVELOPMENT BY AFTERNOON. LATEST GUIDANCE SUGGESTS MOST STORMS SHOULD FORM MAINLY IN THE JAMES RIVER VALLEY REGION...THOUGH SOME CONCERN STILL EXITS A BIT TOWARDS THE WEST. MORNING UPDATE WILL ADDRESS SEVERE CONCERNS LATER TODAY AND HAVE ADJUSTED POPS WITH MORNING GUIDANCE. UPDATES WILL BE OUT SHORTLY. UPDATE ISSUED AT 626 AM CDT SAT JUN 21 2014 WEAK CONVECTION ONGOING ACROSS THE SOUTHWEST. DECIDED TO REMOVE THUNDER FROM FORECAST FOR THE MORNING. OTHERWISE THIS BATCH OF SHOWERS WILL TRACK THROUGH SOUTH CENTRAL NORTH DAKOTA. LATE THIS AFTERNOON STRONGER STORMS WILL FORM ACROSS SOUTH CENTRAL NORTH DAKOTA AS THE COLD FRONT PROGRESSES EAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CDT SAT JUN 21 2014 LATEST SEVERAL HRRR RUNS HAVE INSISTED THAT SHOWER ACTIVITY OVER FAR EASTERN MONTANA WILL HOLD TOGETHER...EVEN EXPANDING AND STRENGTHENING...WILL SLIDE EASTWARD THIS MORNING AND THEN DISSIPATE OVER SOUTHEASTERN NORTH DAKOTA. IT SEEMS REASONABLE BASED ON THE PAST FEW HOURS OF SATELLITE AND RADAR INTERROGATION. THE MORE PRESSING CONCERN IS FOR POSSIBLE SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING SOUTH OF INTERSTATE 94. SPC SLID THEIR CONVECTIVE OUTLOOK SLIGHT RISK TO THE NORTH THIS MORNING. ML CAPE IS EXPECTED TO BE IN THE 1500 J/KG BALLPARK...AND SHEAR WILL BE SUPPORTIVE OF SUPERCELLS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 327 AM CDT SAT JUN 21 2014 THE EXTENDED PERIOD WILL BE MODERATELY ACTIVE FOR THIS TIME OF THE YEAR WITH TWO FEATURES BRINGING PRECIPITATION TO THE REGION. FIRST THE REMNANTS OF THE UPPER LOW ACROSS SASK/MANT WILL SWING SOUTH THROUGH THE NORTHERN PLAINS MONDAY AND TUESDAY BRINGING SCATTERED SHOWERS/THUNDERSTORMS TO THE REGION. SUFFICIENT INSTABILITY EXISTS FOR ROUTINE THUNDERSTORMS WITH NOTHING SCREAMING SEVERE POTENTIAL AT THIS TIME. A CHANGE TO COOLER WEATHER ALSO IS ANTICIPATED AS THIS LOW WILL BRING COOLER H850 TEMPS WITH IT. FOLLOWING THIS THE ECMWF/GFS BOTH ARE BRINGING EASTERN PACIFIC SHORTWAVE ENERGY INTO WESTERN NORTH AMERICA AND ARE CARVING OUT A LONGWAVE TROUGH ACROSS THE WESTERN US. THE EUROPEAN SEEMS TO BE MORE AGGRESSIVE WITH A FASTER AND DEEPER TROUGH. EITHER WAY THE RESULT WILL BE A SOUTHWEST FLOW ALOFT...WITH AN OPENING TO GULF MOISTURE AND EVENTUALLY A MORE ACTIVE THUNDERSTORM PATTERN FOR THE LAST WEEK OF JUNE. USING ALLBLEND GUIDANCE RESULTS IN A CHANCE OF THUNDERSTORMS WEDNESDAY TROUGH FRIDAY WITH NORMAL TO ABOVE NORMAL TEMPERATURES RETURNING BY THE END OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 626 AM CDT SAT JUN 21 2014 AN AREA OF SHOWERS SHOULD MOVE EASTWARD FROM KDIK TO KBIS AND KJMS. ANOTHER ROUND OF STRONGER THUNDERSTORMS SHOULD FORM AROUND 21Z NEAR KBIS/KJMS. KISN/KMOT SHOULD REMAIN DRY AND VFR. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJS SHORT TERM...SCHECK LONG TERM...WAA VIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
630 AM CDT SAT JUN 21 2014 .UPDATE... ISSUED AT 626 AM CDT SAT JUN 21 2014 WEAK CONVECTION ONGOING ACROSS THE SOUTHWEST. DECIDED TO REMOVE THUNDER FROM FORECAST FOR THE MORNING. OTHERWISE THIS BATCH OF SHOWERS WILL TRACK THROUGH SOUTH CENTRAL NORTH DAKOTA. LATE THIS AFTERNOON STRONGER STORMS WILL FORM ACROSS SOUTH CENTRAL NORTH DAKOTA AS THE COLD FRONT PROGRESSES EAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CDT SAT JUN 21 2014 LATEST SEVERAL HRRR RUNS HAVE INSISTED THAT SHOWER ACTIVITY OVER FAR EASTERN MONTANA WILL HOLD TOGETHER...EVEN EXPANDING AND STRENGTHENING...WILL SLIDE EASTWARD THIS MORNING AND THEN DISSIPATE OVER SOUTHEASTERN NORTH DAKOTA. IT SEEMS REASONABLE BASED ON THE PAST FEW HOURS OF SATELLITE AND RADAR INTERROGATION. THE MORE PRESSING CONCERN IS FOR POSSIBLE SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING SOUTH OF INTERSTATE 94. SPC SLID THEIR CONVECTIVE OUTLOOK SLIGHT RISK TO THE NORTH THIS MORNING. ML CAPE IS EXPECTED TO BE IN THE 1500 J/KG BALLPARK...AND SHEAR WILL BE SUPPORTIVE OF SUPERCELLS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 327 AM CDT SAT JUN 21 2014 THE EXTENDED PERIOD WILL BE MODERATELY ACTIVE FOR THIS TIME OF THE YEAR WITH TWO FEATURES BRINGING PRECIPITATION TO THE REGION. FIRST THE REMNANTS OF THE UPPER LOW ACROSS SASK/MANT WILL SWING SOUTH THROUGH THE NORTHERN PLAINS MONDAY AND TUESDAY BRINGING SCATTERED SHOWERS/THUNDERSTORMS TO THE REGION. SUFFICIENT INSTABILITY EXISTS FOR ROUTINE THUNDERSTORMS WITH NOTHING SCREAMING SEVERE POTENTIAL AT THIS TIME. A CHANGE TO COOLER WEATHER ALSO IS ANTICIPATED AS THIS LOW WILL BRING COOLER H850 TEMPS WITH IT. FOLLOWING THIS THE ECMWF/GFS BOTH ARE BRINGING EASTERN PACIFIC SHORTWAVE ENERGY INTO WESTERN NORTH AMERICA AND ARE CARVING OUT A LONGWAVE TROUGH ACROSS THE WESTERN US. THE EUROPEAN SEEMS TO BE MORE AGGRESSIVE WITH A FASTER AND DEEPER TROUGH. EITHER WAY THE RESULT WILL BE A SOUTHWEST FLOW ALOFT...WITH AN OPENING TO GULF MOISTURE AND EVENTUALLY A MORE ACTIVE THUNDERSTORM PATTERN FOR THE LAST WEEK OF JUNE. USING ALLBLEND GUIDANCE RESULTS IN A CHANCE OF THUNDERSTORMS WEDNESDAY TROUGH FRIDAY WITH NORMAL TO ABOVE NORMAL TEMPERATURES RETURNING BY THE END OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 626 AM CDT SAT JUN 21 2014 AN AREA OF SHOWERS SHOULD MOVE EASTWARD FROM KDIK TO KBIS AND KJMS. ANOTHER ROUND OF STRONGER THUNDERSTORMS SHOULD FORM AROUND 21Z NEAR KBIS/KJMS. KISN/KMOT SHOULD REMAIN DRY AND VFR. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...SCHECK LONG TERM...WAA AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
349 AM CDT SAT JUN 21 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CDT SAT JUN 21 2014 LATEST SEVERAL HRRR RUNS HAVE INSISTED THAT SHOWER ACTIVITY OVER FAR EASTERN MONTANA WILL HOLD TOGETHER...EVEN EXPANDING AND STRENGTHENING...WILL SLIDE EASTWARD THIS MORNING AND THEN DISSIPATE OVER SOUTHEASTERN NORTH DAKOTA. IT SEEMS REASONABLE BASED ON THE PAST FEW HOURS OF SATELLITE AND RADAR INTERROGATION. THE MORE PRESSING CONCERN IS FOR POSSIBLE SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING SOUTH OF INTERSTATE 94. SPC SLID THEIR CONVECTIVE OUTLOOK SLIGHT RISK TO THE NORTH THIS MORNING. ML CAPE IS EXPECTED TO BE IN THE 1500 J/KG BALLPARK...AND SHEAR WILL BE SUPPORTIVE OF SUPERCELLS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 327 AM CDT SAT JUN 21 2014 THE EXTENDED PERIOD WILL BE MODERATELY ACTIVE FOR THIS TIME OF THE YEAR WITH TWO FEATURES BRINGING PRECIPITATION TO THE REGION. FIRST THE REMNANTS OF THE UPPER LOW ACROSS SASK/MANT WILL SWING SOUTH THROUGH THE NORTHERN PLAINS MONDAY AND TUESDAY BRINGING SCATTERED SHOWERS/THUNDERSTORMS TO THE REGION. SUFFICIENT INSTABILITY EXISTS FOR ROUTINE THUNDERSTORMS WITH NOTHING SCREAMING SEVERE POTENTIAL AT THIS TIME. A CHANGE TO COOLER WEATHER ALSO IS ANTICIPATED AS THIS LOW WILL BRING COOLER H850 TEMPS WITH IT. FOLLOWING THIS THE ECMWF/GFS BOTH ARE BRINGING EASTERN PACIFIC SHORTWAVE ENERGY INTO WESTERN NORTH AMERICA AND ARE CARVING OUT A LONGWAVE TROUGH ACROSS THE WESTERN US. THE EUROPEAN SEEMS TO BE MORE AGGRESSIVE WITH A FASTER AND DEEPER TROUGH. EITHER WAY THE RESULT WILL BE A SOUTHWEST FLOW ALOFT...WITH AN OPENING TO GULF MOISTURE AND EVENTUALLY A MORE ACTIVE THUNDERSTORM PATTERN FOR THE LAST WEEK OF JUNE. USING ALLBLEND GUIDANCE RESULTS IN A CHANCE OF THUNDERSTORMS WEDNESDAY TROUGH FRIDAY WITH NORMAL TO ABOVE NORMAL TEMPERATURES RETURNING BY THE END OF THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 327 AM CDT SAT JUN 21 2014 AN AREA OF SHOWERS AND THUNDERSTORMS SHOULD FORM BEFORE SUNRISE AND MOVE EASTWARD FROM KDIK TO KBIS AND KJMS. ANOTHER ROUND OF STRONGER THUNDERSTORMS SHOULD FORM AROUND 21Z NEAR KBIS/KJMS. KISN/KMOT SHOULD REMAIN DRY AND VFR. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SCHECK LONG TERM...WAA AVIATION...SCHECK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
102 AM CDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1241 AM CDT SAT JUN 21 2014 THE 03 AND 04 UTC HRRR RUNS HAVE INSISTED THAT PRECIPITATION OVER SOUTHEASTERN MONTANA WILL PROPAGATE INTO SOUTHERN NORTH DAKOTA AROUND 10 UTC...THEN SLIDE EASTWARD INTO THE JAMES RIVER VALLEY BY 17 UTC. RECENT SATELLITE IMAGERY AND 00 UTC NAM AGREE THAT A PORTION OF THE SOUTHERN ALBERTA MIDDLE LEVEL VORTICITY MAXIMUM WILL BREAK OFF AND STREAM EASTWARD EARLY THIS MORNING...AND BUFKIT SOUNDINGS DO INDICATE THERMODYNAMIC INSTABILITY. NO SEVERE WEATHER IS EXPECTED WITH THIS EARLY MORNING PRECIPITATION. THE MAIN WEATHER THREAT WILL BE THIS AFTERNOON AS THE LATEST SPC CONVECTIVE OUTLOOK INCLUDES SOUTHERN NORTH DAKOTA IN A SLIGHT RISK FOR SEVERE. UPDATE ISSUED AT 931 PM CDT FRI JUN 20 2014 ADJUSTED POPS TO REFLECT THE SHOWERS AND THUNDERSTORMS MOVING THROUGH NORTHWEST AND NORTH CENTRAL NORTH DAKOTA. SHOWERS WILL TAPER OFF BY 04 UTC FOLLOWING SUNSET. SKY COVER WAS ALSO ADJUSTED/INCREASED IN AREAS OF POPS. OTHERWISE...NO CHANGES WERE NEEDED. UPDATE ISSUED AT 544 PM CDT FRI JUN 20 2014 DID EXTENDED THE ISOLATED TO SCATTERED MENTION OF SHOWERS AND THUNDERSTORMS THROUGH 02 UTC FOR THE FAR NORTHWEST AND NORTH CENTRAL GIVEN UPSTREAM RADAR TRENDS ACROSS NORTHEAST MONTANA AND THE 20-21 UTC RAP/HRRR. OTHERWISE...NO OTHER CHANGES REQUIRED. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 320 PM CDT FRI JUN 20 2014 THE MAIN FORECAST CONCERN FOR THE PERIOD WILL BE THE SEVERE THUNDERSTORM POTENTIAL SATURDAY AFTERNOON. A VERTICALLY STACKED LOW CENTERED OVER SOUTHERN SASKATCHEWAN AND MANITOBA WILL CONTINUE TO WOBBLE NORTH THIS AFTERNOON AND TONIGHT. EVEN THOUGH INSTABILITY IS DEVELOPING OVER WESTERN AND CENTRAL NORTH DAKOTA THIS AFTERNOON...LARGE SCALE SYNOPTIC SUBSIDENCE (USING 700MB-300MB LAYER Q-VECTOR DIVERGENCE AS A PROXY) SHOULD KEEP CONVECTION FROM GROWING UPSCALE. ISOLATED THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE ACROSS THE INTERNATIONAL BORDER THIS AFTERNOON AND EARLY EVENING...BUT SHOULD BE SHORT-LIVED FOR THE MOST PART. NO SEVERE WEATHER IS EXPECTED AT THIS TIME. FOR TONIGHT...DRY BOUNDARY LAYER CONDITIONS COMBINED WITH WEAK WINDS SHOULD ALLOW TEMPERATURES TO RADIATE TO NEAR NORMAL LOWS. WINDS WILL BE THE WEAKEST IN THE BOUNDARY LAYER ACROSS SOUTHWESTERN NORTH DAKOTA AROUND DAYBREAK. AS A RESULT...THINK PATCHY FOG WILL DEVELOP MAINLY IN THE LOW-LYING AREAS OF SOUTHWESTERN NORTH DAKOTA FROM 09Z-13Z SATURDAY. FOR SATURDAY...THE SHORT RANGE MODELS PROG A SURFACE TROUGH TO ENTER WESTERN NORTH DAKOTA IN THE MORNING...THEN SLOWLY MIGRATE EAST INTO CENTRAL NORTH DAKOTA BY THE AFTERNOON. MUCAPE VALUES ARE FORECAST TO RANGE BETWEEN 1000-1500 J/KG EAST OF A LINE FROM BOWMAN TO DICKINSON...NORTHEAST TO MINOT AND BOTTINEAU BY THE AFTERNOON WITH LITTLE TO NO CIN. FURTHERMORE...0-6 KM BULK SHEAR VALUES AROUND 30 KNOTS ARE FORECAST TO DEVELOP OVER WESTERN AND CENTRAL NORTH DAKOTA DURING THE AFTERNOON AS WELL. THINK CONVECTION WILL HAVE NO PROBLEM INITIATING ALONG THE SURFACE BOUNDARY BY MID-AFTERNOON...WITH GENERALLY AN EASTWARD PROPAGATION THROUGH LATE AFTERNOON. GIVEN THE INSTABILITY/SHEAR PARAMETERS IN PLACE...THINK SOME THUNDERSTORMS COULD BECOME SEVERE ACROSS SOUTH CENTRAL NORTH DAKOTA BY LATE AFTERNOON. WILL MENTION THE SEVERE THREAT IN THE HWO FOR NOW...WITH LATER SHIFTS POSSIBLY ADDING THE SEVERE POTENTIAL IN THE ZONES. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 320 PM CDT FRI JUN 20 2014 SHOWERS / THUNDERSTORMS ALONG THE WEAK SURFACE TROUGH WILL CONTINUE TO MOVE EAST SATURDAY NIGHT. THE MAIN RAIN CHANCES SHOULD BE ACROSS THE EASTERN HALF OF THE FORECAST AREA...WITH THE PRECIPITATION GRADUALLY ENDING FROM WEST TO EAST. DRIER WEATHER IS IN STORE FOR SUNDAY...HOWEVER THE PROXIMITY OF THE UPPER LOW COULD STILL BRING AN ISOLATED SHOWER OR THUNDERSTORM TO FAR NORTHERN NORTH DAKOTA...ESPECIALLY DURING THE AFTERNOON. THE UPPER LOW CONTINUES TO WEAKEN BY MONDAY...GRADUALLY BECOMING MORE OF AN OPEN TROUGH THAT DROPS SOUTH INTO NORTH DAKOTA FROM SOUTHERN CANADA. THE NAM AND GFS AGAIN SUGGEST THERE COULD BE A FEW SHOWERS AND THUNDERSTORMS ACROSS NORTHERN NORTH DAKOTA...WHILE THE ECMWF KEEPS THE RAIN CONFINED TO CANADA. WILL HOLD ONTO SLIGHT CHANCE POPS IN THE SOUTH...WITH THE HIGHER CHANCES IN THE NORTH...CLOSER TO THE BETTER UPPER LEVEL FORCING. THE UPPER TROUGH CONTINUES TO SWING THROUGH THE NORTHERN PLAINS TUESDAY...BEFORE AN H5 RIDGE BUILDS INTO THE AREA FOR MID-WEEK. FAST MOVING WAVES CONTINUE TO WORK THEIR WAY THROUGH THE RIDGE...SO SMALL POPS PRODUCED FROM THE ALL-BLEND MODEL CONSENSUS LOOK APPROPRIATE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1241 AM CDT SAT JUN 21 2014 AN AREA OF SHOWERS AND THUNDERSTORMS SHOULD FORM BEFORE SUNRISE AND MOVE EASTWARD FROM KDIK TO KBIS AND KJMS. ANOTHER ROUND OF STRONGER THUNDERSTORMS SHOULD FORM AROUND 21Z NEAR KBIS/KJMS. KISN/KMOT SHOULD REMAIN DRY AND VFR. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SCHECK SHORT TERM...TM LONG TERM...CK AVIATION...SCHECK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1051 AM EDT SAT JUN 21 2014 .SYNOPSIS... AN UPPER RIDGE WILL CONTINUE TO BREAK DOWN TODAY RESULTING IN WEAKENING HIGH PRESSURE CURRENTLY IN PLACE OVER THE AREA. THIS SHOULD YIELD A GREATER COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA THROUGH EARLY NEXT WEEK. A TYPICAL WARM SUMMERLIKE PATTERN WILL CONTINUE THROUGH NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 1000 AM UPDATE...SHOWERS THAT FORMED IN UPSLOPE FLOW OVER UPPER EAST TN...AND POSSIBLY AIDED BY MESOSCALE RIPPLES ROUNDING THE UPPER RIDGE...HAVE NOW MOVED INTO OUR NRN MTN ZONES. AS THE RIPPLES MOVE EAST OF THE MTNS DOWNSLOPE FLOW WILL LIKELY WIPE OUT THE CURRENT ACTIVITY...BUT NEW CELLS SHOULD PROPAGATE EWD OUT OF THE FOOTHILLS...MUCH LIKE WHAT WE EXPERIENCED YESTERDAY. THIS IDEA ALSO BACKED UP BY THE LATEST HRRR TRENDS...AND TO SOME EXTENT THE 12Z NAM. THE NEW NAM ALSO STILL FEATURES BEST INSTBY IN THE NC PIEDMONT WHICH ACTUALLY PEAKS AT MIDDAY...WITH LAPSE RATES DIMINISHING LATER IN THE AFTN. HOWEVER UNDER CONTINUED HEATING SOME ACTIVITY WILL LIKELY BE ABLE TO CONTINUE UNTIL AFTER SUNSET AS IT TYPICALLY DOES. SO WHILE ADJUSTMENTS HAVE BEEN MADE TO BETTER REFLECT THE PROPAGATION INTO THE PIEDMONT...PEAK POPS ARE THE SAME. WILL ADJUST TEMPS PER LATEST OBS. PREVIOUS DISCUSSION... AS OF 300 AM EDT SATURDAY...BROAD YET WEAK UPPER RIDGE CONTINUES TO SLOWLY RETROGRADE WESTWARD ALLOWING FOR CONTINUED NORTHWEST FLOW ALOFT FOR THE SOUTHERN APPS. MEANWHILE AT THE SURFACE...WEAK LEE SIDE TROF WILL ONCE AGAIN BE PRESENT ALONG THE MIDATLANTIC COASTLINE WITH A WEAK COASTAL LOW DEVELOPING BY LATE MORNING TO EARLY AFTERNOON. EXPECTING LESS CONVECTIVE COVERAGE OVERALL TODAY WITH THE MAJORITY OF THE ACTIVITY TIED TO THE NC PIEDMONT WHERE INSTABILITY WILL BE HIGHEST...AND WEAK UPPER H5 IMPULSES PASS THROUGH THE MEAN FLOW. GUIDANCE INDICATES A RELATIVELY STABLE AIRMASS WILL RESIDE ACROSS NORTHEAST GA AND THE CENTRAL/WESTERN UPSTATE WILL LITTLE TO NO FORCING AVAILABLE FOR CONVECTION. AS MENTIONED ABOVE...PROFILES WILL BE MOST SUPPORTIVE OF CONVECTION ACROSS THE NC PIEDMONT...ESPECIALLY ALONG THE I40 CORRIDOR WHERE UPWARDS OF 1500J/KG SBCAPE WILL RESIDE. CANNOT RULE OUT A FEW SEVERE THUNDERSTORMS IN THIS REGION DESPITE POOR MID LEVEL LAPSE RATES. THAT SAID...PRIMARY SEVERE THREATS WILL BE DAMAGING DOWNBURST WINDS AND HEAVY RAINFALL AS VERY MOIST PROFILES WATER LOAD UPDRAFTS LEADING TO ENHANCED REGIONS OF DCAPE. POPS WILL RAMP UP BY MID AFTERNOON TO LOW END LIKELY LEVELS EAST OF I77 IN THE NORTHERN NC PIEDMONT...TAPERING TO SLIGHT CHANCE POPS FURTHER SOUTH AND WEST...BEFORE ALL POPS FALL OFF INTO THE OVERNIGHT AS HEATING IS LOST. TEMPERATURES THROUGH THE NEAR TERM PERIOD WILL ONCE AGAIN BE ABOVE NORMAL AS SUMMERTIME DIURNAL PATTERN CONTINUES. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM EDT SATURDAY...H5 HEIGHTS WILL GRADUALLY RISE OVER THE SE CONUS ON SUNDAY AS AN UPPER RIDGE AXIS SHIFTS EASTWARD INTO THE CENTRAL STATES AND POSITIVELY TILTED UPPER TROUGH AXIS MOVES OFF THE EASTERN SEABOARD. MONDAY...AN UPPER RIDGE WILL QUICKLY BUILD IN ACROSS THE REGION FROM THE WEST WITH ITS AXIS CROSSING THE FORECAST AREA BY MON EVENING/NIGHT. AT THE SURFACE...EXPECT N/NELY FLOW TO PERSIST ACROSS THE REGION ON SUNDAY AS A BROAD AREA OF SURFACE LOW DRIFTS EAST AWAY FROM THE CAROLINAS COAST. MODEL SOUNDINGS SUGGEST THAT PROFILES SHOULD REMAIN RATHER DRY DUE TO PREVAILING DOWNSLOPE NORTHERLY FLOW KEEPING THE LCL ELEVATED ABOVE 6K FT. IN RESPONSE TO THIS...MODELS KEEP THE AREA MOSTLY DRY THROUGH THE AFTERNOON. HOWEVER...CONDITIONS SHOULD CHANGE DRAMATICALLY BY SUN EVENING/NIGHT AS THE REGION WILL BE UNDER THE SW PERIPHERY OF THE BERMUDA HIGH BRINGING E/SELY FLOW TO THE FORECAST AREA. IN RESPONSE TO THIS PATTERN...THE NAM AND GFS DEVELOP UPSLOPE INDUCED SHOWERS AND THUNDERSTORMS AREAS ALONG AND EAST OF THE BLUE RIDGE BY SUN EVENING AND CONTINUE THROUGH THE OVERNIGHT HOURS. HENCE...HAVE MENTIONED POPS IN THE 30/40S OVER THE AFOREMENTIONED AREAS SUN NIGHT. MONDAY...MODELS AGREE THAT THE REGION WILL BE UNDER THE CONFLUENT SSW/SSELY FLOW REGIME. WITH THE COMBINATION OF INCREASING GULF/ATLANTIC MOISTURE ADVECTION...LLVL CONVERGENCE AND DIURNAL INSTABILITY...WE WILL SEE WIDESPREAD CONVECTION ONGOING THROUGH LATE EVENING/NIGHT. THIS PATTERN IS SUSCEPTIBLE TO HEAVY RAINFALL WITH LOCALIZED FLASH FLOODING IN TRAINING CELLS. WITH THAT SAID..HAVE INCREASED THE POPS INTO THE 40/50S RANGE ACROSS MUCH OF THE REGION. TEMPERATURES WILL START OUT 2-3 DEGREES ABOVE NORMAL SUN AND COOL DOWN TO NEAR NORMAL RANGE BY MONDAY. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 200 AM EDT SAT...THE LATEST GLOBAL MODELS CONTINUE TO ADVERTISE THAT AN UPPER RIDGE WILL BREAK DOWN OVER THE SE CONUS TUE IN RESPONSE TO AN APPROACHING SHORTWAVE TROUGH FROM THE CENTRAL STATES. THE GFS IS SHARPER WITH THIS WAVE PASSING JUST TO OUR NORTH ON LATE WED/EARLY THU WHILE THE ECMWF IS WEAKER AND TAKES IT INTO THE OHIO VALLEY...LEAVING OUR AREA UNDER NEARLY ZONAL FLOW ALOFT. BOTH MODELS THEN BUILD UPPER RIDGE OVER THE AREA BY FRI. AT THE SURFACE...BERMUDA HIGH WILL CONTINUE TO INFLUENCE THE AREA THROUGH MUCH OF THE MEDIUM RANGE PERIOD WITH A FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER WAVE CROSSING THE FORECAST AREA LATE WED. AS FOR THE SENSIBLE WEATHER...WE WILL CONTINUE TO SEE DIURNALLY DRIVEN PULSE TYPE STORMS ACROSS MUCH OF THE AREA ON EACH DAY GIVEN WEAKLY SHEARED ENVIRONMENT...DIURNAL INSTABILITY AND GULF MOISTURE ADVECTION IN PREDOMINANT S/SWLY FLOW ALOFT. WITH INCREASING SHEAR ALOFT IN LIGHT OF FROPA ON WED...WE MAY SEE BETTER ORGANIZED LINE OF STORMS PRODUCING DAMAGING WIND GUSTS AND LARGE HAIL. TEMPERATURES WILL STAY NEAR NORMAL RANGE THROUGH THE PERIOD. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH THE EXCEPTION OF POSSIBLE AFTERNOON MVFR TSRA. INTRODUCED LOW VFR DIURNAL CU CIG AT 19Z WITH A 4HR TEMPO FOR AFTERNOON TSRA INCLUDING A 4SM VISB. BKN LOW VFR CIGS PREVAIL THROUGH 08Z BEFORE SCT OUT...EVENTUALLY GIVING WAY TO HIGH LEVEL CIRRUS. WINDS WILL REMAIN OUT OF THE WEST NORTHWEST THROUGH MID/LATE MORNING BEFORE LEE SIDE TROF ONCE AGAIN VEERS WINDS FURTHER NORTH FOR THE REMAINDER OF THE PERIOD. ELSEWHERE...MUCH THE SAME AS KCLT ABOVE AS VFR CONDITIONS WILL PREVAIL WITH THE EXCEPTION OF MVFR TSRA IN THE AFTERNOON FOR THE NC SITES. CONVECTION ON SATURDAY WILL LIKELY REMAIN TIED TO THE TERRAIN...AND THE NC PIEDMONT. THUS FEATURE TEMPOS FOR MVFR TSRA AT KAVL AND KHKY WHILE ONLY INCLUDING VCTS MENTION AT THE SC SITES. REINTRODUCED LIFR CIGS WITH IFR VISB AT KAVL NEAR THE END OF THE PERIOD BASED UPON PERSISTENCE OF THE PATTERN. WINDS THROUGH THE PERIOD WILL REMAIN NORTHERLY AND WILL INCREASE TO AROUND 8-10KTS WHEN MIXING IS AT ITS GREATEST DURING PEAK HEATING SATURDAY AFTERNOON. OUTLOOK...ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED AGAIN SUNDAY...WITH THE GREATEST COVERAGE ACROSS THE MTNS AND NC PIEDMONT. RESTRICTIONS MAY OCCUR DURING TSRA AND ALSO IN THE MTN VALLEYS EACH MORNING WHERE LOW CLOUDS AND FOG MAY FORM OVER AREAS OF RECENT RAINFALL. CONFIDENCE TABLE... 15-21Z 21-03Z 03-09Z 09-15Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% MED 79% MED 62% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JOH NEAR TERM...CDG/WIMBERLEY SHORT TERM...JOH LONG TERM...JOH AVIATION...CDG/WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1011 AM EDT SAT JUN 21 2014 .SYNOPSIS... AN UPPER RIDGE WILL CONTINUE TO BREAK DOWN TODAY RESULTING IN WEAKENING HIGH PRESSURE CURRENTLY IN PLACE OVER THE AREA. THIS SHOULD YIELD A GREATER COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA THROUGH EARLY NEXT WEEK. A TYPICAL WARM SUMMERLIKE PATTERN WILL CONTINUE THROUGH NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 1000 AM UPDATE...SHOWERS THAT FORMED IN UPSLOPE FLOW OVER UPPER EAST TN...AND POSSIBLY AIDED BY MESOSCALE RIPPLES ROUNDING THE UPPER RIDGE...HAVE NOW MOVED INTO OUR NRN MTN ZONES. AS THE RIPPLES MOVE EAST OF THE MTNS DOWNSLOPE FLOW WILL LIKELY WIPE OUT THE CURRENT ACTIVITY...BUT NEW CELLS SHOULD PROPAGATE EWD OUT OF THE FOOTHILLS...MUCH LIKE WHAT WE EXPERIENCED YESTERDAY. THIS IDEA ALSO BACKED UP BY THE LATEST HRRR TRENDS...AND TO SOME EXTENT THE 12Z NAM. THE NEW NAM ALSO STILL FEATURES BEST INSTBY IN THE NC PIEDMONT WHICH ACTUALLY PEAKS AT MIDDAY...WITH LAPSE RATES DIMINISHING LATER IN THE AFTN. HOWEVER UNDER CONTINUED HEATING SOME ACTIVITY WILL LIKELY BE ABLE TO CONTINUE UNTIL AFTER SUNSET AS IT TYPICALLY DOES. SO WHILE ADJUSTMENTS HAVE BEEN MADE TO BETTER REFLECT THE PROPAGATION INTO THE PIEDMONT...PEAK POPS ARE THE SAME. WILL ADJUST TEMPS PER LATEST OBS. PREVIOUS DISCUSSION... AS OF 300 AM EDT SATURDAY...BROAD YET WEAK UPPER RIDGE CONTINUES TO SLOWLY RETROGRADE WESTWARD ALLOWING FOR CONTINUED NORTHWEST FLOW ALOFT FOR THE SOUTHERN APPS. MEANWHILE AT THE SURFACE...WEAK LEE SIDE TROF WILL ONCE AGAIN BE PRESENT ALONG THE MIDATLANTIC COASTLINE WITH A WEAK COASTAL LOW DEVELOPING BY LATE MORNING TO EARLY AFTERNOON. EXPECTING LESS CONVECTIVE COVERAGE OVERALL TODAY WITH THE MAJORITY OF THE ACTIVITY TIED TO THE NC PIEDMONT WHERE INSTABILITY WILL BE HIGHEST...AND WEAK UPPER H5 IMPULSES PASS THROUGH THE MEAN FLOW. GUIDANCE INDICATES A RELATIVELY STABLE AIRMASS WILL RESIDE ACROSS NORTHEAST GA AND THE CENTRAL/WESTERN UPSTATE WILL LITTLE TO NO FORCING AVAILABLE FOR CONVECTION. AS MENTIONED ABOVE...PROFILES WILL BE MOST SUPPORTIVE OF CONVECTION ACROSS THE NC PIEDMONT...ESPECIALLY ALONG THE I40 CORRIDOR WHERE UPWARDS OF 1500J/KG SBCAPE WILL RESIDE. CANNOT RULE OUT A FEW SEVERE THUNDERSTORMS IN THIS REGION DESPITE POOR MID LEVEL LAPSE RATES. THAT SAID...PRIMARY SEVERE THREATS WILL BE DAMAGING DOWNBURST WINDS AND HEAVY RAINFALL AS VERY MOIST PROFILES WATER LOAD UPDRAFTS LEADING TO ENHANCED REGIONS OF DCAPE. POPS WILL RAMP UP BY MID AFTERNOON TO LOW END LIKELY LEVELS EAST OF I77 IN THE NORTHERN NC PIEDMONT...TAPERING TO SLIGHT CHANCE POPS FURTHER SOUTH AND WEST...BEFORE ALL POPS FALL OFF INTO THE OVERNIGHT AS HEATING IS LOST. TEMPERATURES THROUGH THE NEAR TERM PERIOD WILL ONCE AGAIN BE ABOVE NORMAL AS SUMMERTIME DIURNAL PATTERN CONTINUES. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM EDT SATURDAY...H5 HEIGHTS WILL GRADUALLY RISE OVER THE SE CONUS ON SUNDAY AS AN UPPER RIDGE AXIS SHIFTS EASTWARD INTO THE CENTRAL STATES AND POSITIVELY TILTED UPPER TROUGH AXIS MOVES OFF THE EASTERN SEABOARD. MONDAY...AN UPPER RIDGE WILL QUICKLY BUILD IN ACROSS THE REGION FROM THE WEST WITH ITS AXIS CROSSING THE FORECAST AREA BY MON EVENING/NIGHT. AT THE SURFACE...EXPECT N/NELY FLOW TO PERSIST ACROSS THE REGION ON SUNDAY AS A BROAD AREA OF SURFACE LOW DRIFTS EAST AWAY FROM THE CAROLINAS COAST. MODEL SOUNDINGS SUGGEST THAT PROFILES SHOULD REMAIN RATHER DRY DUE TO PREVAILING DOWNSLOPE NORTHERLY FLOW KEEPING THE LCL ELEVATED ABOVE 6K FT. IN RESPONSE TO THIS...MODELS KEEP THE AREA MOSTLY DRY THROUGH THE AFTERNOON. HOWEVER...CONDITIONS SHOULD CHANGE DRAMATICALLY BY SUN EVENING/NIGHT AS THE REGION WILL BE UNDER THE SW PERIPHERY OF THE BERMUDA HIGH BRINGING E/SELY FLOW TO THE FORECAST AREA. IN RESPONSE TO THIS PATTERN...THE NAM AND GFS DEVELOP UPSLOPE INDUCED SHOWERS AND THUNDERSTORMS AREAS ALONG AND EAST OF THE BLUE RIDGE BY SUN EVENING AND CONTINUE THROUGH THE OVERNIGHT HOURS. HENCE...HAVE MENTIONED POPS IN THE 30/40S OVER THE AFOREMENTIONED AREAS SUN NIGHT. MONDAY...MODELS AGREE THAT THE REGION WILL BE UNDER THE CONFLUENT SSW/SSELY FLOW REGIME. WITH THE COMBINATION OF INCREASING GULF/ATLANTIC MOISTURE ADVECTION...LLVL CONVERGENCE AND DIURNAL INSTABILITY...WE WILL SEE WIDESPREAD CONVECTION ONGOING THROUGH LATE EVENING/NIGHT. THIS PATTERN IS SUSCEPTIBLE TO HEAVY RAINFALL WITH LOCALIZED FLASH FLOODING IN TRAINING CELLS. WITH THAT SAID..HAVE INCREASED THE POPS INTO THE 40/50S RANGE ACROSS MUCH OF THE REGION. TEMPERATURES WILL START OUT 2-3 DEGREES ABOVE NORMAL SUN AND COOL DOWN TO NEAR NORMAL RANGE BY MONDAY. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 200 AM EDT SAT...THE LATEST GLOBAL MODELS CONTINUE TO ADVERTISE THAT AN UPPER RIDGE WILL BREAK DOWN OVER THE SE CONUS TUE IN RESPONSE TO AN APPROACHING SHORTWAVE TROUGH FROM THE CENTRAL STATES. THE GFS IS SHARPER WITH THIS WAVE PASSING JUST TO OUR NORTH ON LATE WED/EARLY THU WHILE THE ECMWF IS WEAKER AND TAKES IT INTO THE OHIO VALLEY...LEAVING OUR AREA UNDER NEARLY ZONAL FLOW ALOFT. BOTH MODELS THEN BUILD UPPER RIDGE OVER THE AREA BY FRI. AT THE SURFACE...BERMUDA HIGH WILL CONTINUE TO INFLUENCE THE AREA THROUGH MUCH OF THE MEDIUM RANGE PERIOD WITH A FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER WAVE CROSSING THE FORECAST AREA LATE WED. AS FOR THE SENSIBLE WEATHER...WE WILL CONTINUE TO SEE DIURNALLY DRIVEN PULSE TYPE STORMS ACROSS MUCH OF THE AREA ON EACH DAY GIVEN WEAKLY SHEARED ENVIRONMENT...DIURNAL INSTABILITY AND GULF MOISTURE ADVECTION IN PREDOMINANT S/SWLY FLOW ALOFT. WITH INCREASING SHEAR ALOFT IN LIGHT OF FROPA ON WED...WE MAY SEE BETTER ORGANIZED LINE OF STORMS PRODUCING DAMAGING WIND GUSTS AND LARGE HAIL. TEMPERATURES WILL STAY NEAR NORMAL RANGE THROUGH THE PERIOD. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH THE EXCEPTION OF POSSIBLE AFTERNOON MVFR TSRA. INITIALIZED TAF UNDER BKN MID LEVEL STRATUS THROUGH MID/LATE MORNING WHERE STEEPENING LAPSE RATES ALLOW FOR DIURNAL CU DEVELOPMENT. INTRODUCED LOW VFR CU CIG AT 19Z WITH A 4HR TEMPO FOR AFTERNOON TSRA INCLUDING A 4SM VISB. BKN LOW VFR CIGS PREVAIL THROUGH 08Z BEFORE SCT OUT...EVENTUALLY GIVING WAY TO HIGH LEVEL CIRRUS. WINDS WILL REMAIN OUT OF THE WEST NORTHWEST THROUGH MID/LATE MORNING BEFORE LEE SIDE TROF ONCE AGAIN VEERS WINDS FURTHER NORTH FOR THE REMAINDER OF THE PERIOD. ELSEWHERE...MUCH THE SAME AS KCLT ABOVE AS VFR CONDITIONS WILL PREVAIL WITH THE EXCEPTION OF MVFR TSRA IN THE AFTERNOON FOR THE NC SITES. CONVECTION ON SATURDAY WILL LIKELY REMAIN TIED TO THE TERRAIN...AND THE NC PIEDMONT. THUS FEATURE TEMPOS FOR MVFR TSRA AT KAVL AND KHKY WHILE ONLY INCLUDING VCTS MENTION AT THE SC SITES. REINTRODUCED LIFR CIGS WITH IFR VISB AT KAVL NEAR THE END OF THE PERIOD BASED UPON PERSISTENCE OF THE PATTERN. WINDS THROUGH THE PERIOD WILL REMAIN NORTHERLY AND WILL INCREASE TO AROUND 8-10KTS WHEN MIXING IS AT ITS GREATEST DURING PEAK HEATING SATURDAY AFTERNOON. OUTLOOK...ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED THIS WEEKEND...WITH THE GREATEST COVERAGE ACROSS THE MTNS AND NC PIEDMONT. RESTRICTIONS MAY OCCUR DURING TSRA AND ALSO IN THE MTN VALLEYS EACH MORNING WHERE LOW CLOUDS AND FOG MAY FORM OVER AREAS OF RECENT RAINFALL. CONFIDENCE TABLE... 14-20Z 20-02Z 02-08Z 08-14Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 92% HIGH 100% MED 77% LOW 57% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JOH NEAR TERM...CDG/WIMBERLEY SHORT TERM...JOH LONG TERM...JOH AVIATION...CDG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
149 AM EDT SAT JUN 21 2014 .SYNOPSIS... AN UPPER RIDGE WILL CONTINUE TO BREAK DOWN TODAY RESULTING IN WEAKENING HIGH PRESSURE CURRENTLY IN PLACE OVER THE AREA. THIS SHOULD YIELD A GREATER COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA THROUGH EARLY NEXT WEEK. A TYPICAL WARM SUMMERLIKE PATTERN WILL CONTINUE THROUGH NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 145 AM EDT SATURDAY...REMNANTS OF TENNESSEE VALLEY MCS ARE PUSHING INTO THE NORTHERN MTNS AT THIS TIME. HOWEVER...DUE TO WEAK INSTABILITY NOT EXPECTING THESE SHOWERS AND THUNDERSTORMS TO SURVIVE MUCH LONGER...ESPECIALLY ONCE INTERACTING WITH THE TERRAIN. LIKEWISE...EARLIER SHOWER/THUNDERSTORM ACTIVITY ACROSS PORTIONS OF THE I77 CORRIDOR HAS EXITED TO THE EAST...AND WEAKENED. THUS...POPS WILL TAPER DOWN INTO THE REMAINDER OF THE MORNING ACROSS THE PIEDMONT AS EXPECTED...WITH CHANCE POPS LINGERING ALONG THE SPINE OF THE APPS. OTHERWISE...NO SIGNIFICANT CHANGES MADE TO THE EXTREME NEAR TERM PORTION OF THE FORECAST. DID TWEAK TEMPS/DEWPOINTS/VISB TO REFLECT LATEST OBSERVATIONS. PREVIOUS DISCUSSION... EVENING UPDATE...LATEST REGIONAL COMP REF SHOWS WEAKENING CONVECTION IN AND AROUND THE CWFA...WHICH AGREES WELL WITH THE DIFFUSE ENERGY FIELD ALOFT. THERE COULD BE SOME TSTMS AFFECTING THE NRN MTNS OVERNIGHT ASSOCIATED WITH AN MCS SRN FLANK OUTFLOW...HOWEVER NOT EXPECTING ANY MORE THAN A FEW LIGHTNING STRIKES AND LOCALIZED GUSTY WINDS. SOME MTN VALLEY FG IS POSSIBLE...BUT NOT TOO CERTAIN WITH THE AMOUNT OF DEBRIS CLOUDS MOVING IN FROM THE NW. THE GOING POPS ARE IN GOOD SHAPE AND MADE ONLY MINOR ADJS TO THE MIN TEMP GRID. 730 PM EDT UPDATE...A NICE LOBE OF VORT ENERGY HAS SPAWNED A LINE OF STRONG TO SEVERE CONVECTION ACROSS THE NC MTNS AND FTHILLS THIS EVENING. THE STEERING FLOW HAS INCREASED AS WELL AND STRENGTHENED INFLOW CONVERGENT UPDRAFTS. ANTICIPATE A WEAKENING TREND AS THESE STORMS MOVE OUT OF THE HIGHER TERRAIN INTO MORE STABLE AIR OVER THE NEXT COUPLE HRS. HAVE RECEIVED A FEW REPORTS OF FUNNEL CLOUDS WHICH ARE POSSIBLE WITH THE LVLV ROTATING UPDRAFTS. HOWEVER...A COUPLE REPORTS HAVE INDICATED TORNADOES ON THE GROUND...WHICH ARE NOT POSSIBLE IN THE CURRENT LOW SHEAR ENVIRONMENT. THESE REPORTS ARE LIKELY SCUD CLOUDS AND/OR CLOUDS ASSOCIATED WITH STRONG RAINSHAFTS. MADE MINOR TWEAKS TO THE T/TDS GRIDS DUE TO PRECIP OVER THE PAST 3 HRS. 430 PM EDT UPDATE...LOW SFC TD/S AND A NOTABLE LOBE OF DNVA HAS KEPT CONVECTION MINIMAL AND RELATIVELY SHORT LIVED ACROSS CWFA THUS FAR THIS AFTERNOON. THE STORMS TO THE EAST HAVE BEEN ABLE TO TAP INTO HIGH VALUES OF DCAPE AND PRODUCE SEVERE WINDS...BUT THE REMAINING CELLS HAVE HAD FAIRLY NARROW AND WEAKER UPDRAFTS. THE NAM12 HAS A GOOD HANDLE ON THE UPPER VORT FIELD AND WILL FOLLOW IT/S GUIDANCE WRT TO POPS AND CONVEC INITIATION OVER THE NEXT COUPLE HRS. THE UPSTATE HAS THE LOWEST INSTABILITY COMBINED WITH NEGATIVE ULVL FORCING...SO POPS WILL BE LOWERED TO ISOL THERE...ACROSS THE SRN NC FTHILLS. THE BEST CHANCE FOR NEW DEVELOPMENT WILL BE ACROSS THE NC MTN SPINE WHERE ENHANCED CONVECTION SHOULD MOVE IN AND LIKELY WEAKEN THROUGH 8 PM. AS OF 200 PM EDT...CELLS NOW LINING UP ALONG THE BLUE RIDGE AS A WEAK RIPPLE ROUNDS THE RIDGE OVER THE LOWER MISSISSIPPI VALLEY AND MOVES SEWD ACRS THE AREA. HRRR SEEMS TO HAVE PICKED UP ON THIS ACTIVITY AND ALLOWS IT TO PROPAGATE SEWD SLIGHTLY BEFORE DISSIPATING...POSSIBLY DUE TO DOWNSLOPING BY THE NW FLOW ABOVE THE BOUNDARY LAYER. THE NCEP HIRES WINDOW /NMM/ SUGGESTS THE SAME...BUT DEVELOPS A NEW ROUND OF CONVECTION IN THE MTNS BEHIND IT WHICH FILLS IN THE SAME AREA. DEWPOINTS HAVE MIXED OUT SLIGHTLY AS EXPECTED...BUT NOT ENOUGH TO KEEP SBCAPE FROM RISING TO 2000 J OR MORE PER SPC MESOANALYSIS. NO SEVERE REPORTS HAVE YET BEEN RECEIVED BUT A FEW STORMS HAVE MET WARNING CRITERIA. I AM NO LONGER CONFIDENT IN OUR EARLIER EXPECTATIONS THAT WE WOULD NOT GET UNSTABLE ENOUGH FOR LARGE HAIL TO BE MUCH OF A CONCERN...BUT PROFILES REMAIN DRY ENOUGH FOR DCAPES OF 700-1000 J SUPPORTING A MICROBURST THREAT. CHC RANGE POPS HAVE BEEN MAINTAINED ACRS MOST OF THE AREA...BUT NOW THE GREATEST CHANCE APPEARS TO BE DOWNSTREAM OF THE CURRENT ACTIVITY. SOME MODELS INCLUDING THE NAM TRY TO DEVELOP ANOTHER ROUND OF CONVECTION AFTER SUNSET...BUT PROFILES HAVE ENOUGH CIN THAT I THINK THIS IS UNLIKELY IN THE PRESENCE OF SUCH WEAK FORCING. POPS DIMINISH EAST OF THE MTNS BY LATE EVENING. MAIN FORECAST CHALLENGE FOR THE OVERNIGHT IS WHETHER ANY ACTIVITY WILL MOVE INTO OUR AREA FROM THE WEST...AS SUGGESTED BY SOME OF THE MESO GUIDANCE AND THE 12Z NAM. THE NAM SHOWS AN MCV DEVELOPING OVER THE OHIO VALLEY LATE THIS AFTN AND PROGRESSING SEWD ACRS KY/TN...THE ORIGINAL CONVECTION DYING BUT THE MCV KICKING OFF NEW DEVELOPMENT ON THE WEST SLOPES OF THE MTNS WHICH THEN MOVES INTO NW NC AROUND DAYBREAK. SO FAR THE NAM DEPICTION OF THE ORIGINATING CONVECTION SEEMS OVERDONE...SO WILL ONLY GIVE THIS SMALL WEIGHT IN THE FCST. CLOUD COVER PROGGED BY THE MODELS APPEARS MAINLY TO BE CONVECTIVE DEBRIS AND IT IS A BIT HARDER TO HEDGE ON THAT. THE NAM SUGGESTS DEEP RH WILL BE HIGHER ON SATURDAY...PROBABLY SINCE IT EXPECTS DEBRIS TO COME IN DURING THE MORNING. GFS PROFILES REALLY DO NOT LOOK TOO MUCH DIFFERENT FROM TODAY...THOUGH SBCAPE IS STILL LOWER DUE TO SLIGHTLY WEAKER LAPSE RATES. THE DIFFERENCE IS NOT ONLY IMPORTANT FOR THE POTENTIALLY SIGNIFICANT REDUCTION IN INSTABILITY DUE TO CLOUDIER SKIES...BUT FOR A REDUCTION IN DCAPE AND MITIGATED SEVERE RISK. SPC FEATURES A 5 PCT AREA JUST TO OUR EAST WHERE WEAK SHORTWAVE /THE POTENTIAL MCV/ WILL PASS OVER DURING PEAK HEATING. IT DOES APPEAR THE BEST PRECIP CHANCES OVERALL WILL BE DURING THE MORNING IN THE NORTHERN FA AND THEN OVER THE I-77 CORRIDOR DURING THE AFTN WHERE THE BEST BUOYANCY IS SUGGESTED. TEMPS TONIGHT AND TOMORROW WILL REMAIN A CATEGORY OR SO ABOVE CLIMO. && .SHORT TERM /TONIGHT THROUGH MONDAY/... AS OF 200 PM FRIDAY...HEIGHTS WILL GRADUALLY FALL THROUGH EARLY NEXT WEEK...AS UPPER HIGH CONTINUES TO WEAKEN AND RETROGRADE TOWARDS THE WESTERN GULF OF MEXICO. THIS WILL ALSO ALLOW WEAK FRONTAL ZONE TO BACK DOOR ITS WAY THROUGH THE AREA BY SUNDAY...POSSIBLY INTRODUCING SLIGHTLY COOLER AND DRIER AIR. THIS IS NOT EXPECTED TO ELIMINATE INSTABILITY ENOUGH TO HALT DIURNAL CONVECTION...BUT COVERAGE OF SUNDAY AFTERNOON/EVENING CONVECTION IS EXPECTED TO BE MORE TYPICAL OF WHAT ONE WOULD EXPECT THIS TIME OF YEAR (30-40 POPS MTNS...20/30 PIEDMONT). BY MONDAY... SHORT TERM MODELS DEPICT ESTABLISHMENT OF AN E/SE FLOW IN ASSOCIATION WITH A WEAK INVERTED RIDGE ALONG THE EASTERN SEABOARD. THIS UPSLOPE FLOW COULD SUPPORT A BIT MORE IN THE WAY OF DIURNAL CONVECTION BY MONDAY AFTERNOON...SO POPS RETURN TO ABOVE CLIMO BY THIS TIME. WEAK SHEAR WITH HALFWAY DECENT STEERING FLOW SHOULD PRECLUDE ANYTHING MORE THAN A TYPICAL EARLY SUMMER PULSE SEVERE THREAT OR FLASH FLOODING THREAT SUNDAY. HOWEVER...HEAVY RAINFALL MAY BECOME AN ISSUE MONDAY...AS UPPER FLOW WEAKENS ABOVE THE LOW LEVEL SOUTHEAST FLOW...POSSIBLY FAVORING ANCHORING OF CELLS ACROSS PORTIONS OF THE HIGH TERRAIN. TEMPS ARE EXPECTED TO RETURN TO NEAR CLIMO BY MONDAY IN THE RELATIVELY COOL E/SE FLOW REGIME. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 130 PM EDT FRIDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON TUESDAY WITH WEAK UPPER RIDGING OVER THE SE CONUS AND A LOW AMPLITUDE UPPER TROF DIGGING DOWN OVER OVER THE DAKOTAS AND MINNESOTA. OVER THE NEXT FEW DAYS...THE TROF SLOWLY PROPAGATES EASTWARD...YET IT DOES NOT APPEAR TO MAKE MUCH HEADWAY SOUTHWARD. THE LONG RANGE MODELS HAVE BEEN DIFFERING A FAIR AMOUNT WRT THE AMPLIFICATION OF THIS TROF...BUT ITS LOOKING LIKE THEY ARE LEANING MORE TOWARDS STRONGER RIDGING OVER OUR FCST AREA THRU DAY 7. THIS PATTERN LEAVES OUR AREA UNDER GENERALLY WEAK WEST TO SWLY STEERING FLOW THRU THE PERIOD. AT THE SFC...THE REGION WILL BE UNDER THE INFLUENCE OF THE BERMUDA HIGH FOR MOST OF THE PERIOD WITH A COLD FRONT APPROACHING THE CAROLINAS BY EARLY WED AND WASHING OUT AS IT MOVES OVER THE CWFA. IN ITS WAKE...WEAK CANADIAN HIGH PRESSURE TRIES TO PUSH SOUTHWARD FROM NEW ENGLAND BUT ITS PROGRESS IS SUPPRESSED BY THE BERMUDA HIGH. WITH THE COMBINATION OF SLY MOIST FLOW...A WEAKLY SHEARED ENVIRONMENT AND MODERATE DIURNAL BUOYANCY...WE STILL HAVE A SOLID CHANCE OF PULSE TYPE CONVECTION ACROSS MUCH OF THE REGION EACH DAY...FAVORING IN THE MTN ZONES OVERALL. TEMPERATURES SHOULD REMAIN FAIRLY STEADY WITH VALUES NEAR NORMAL OR POSSIBLE A FEW DEGREES WARMER. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH THE EXCEPTION OF POSSIBLE AFTERNOON MVFR TSRA. INITIALIZED TAF UNDER SCT LOW VFR STRATUS WITH BKN MID LEVEL CIG THROUGH MID/LATE MORNING WHERE STEEPENING LAPSE RATES ALLOW FOR DIURNAL CU DEVELOPMENT. INTRODUCED LOW VFR CU CIG AT 19Z WITH A 4HR PROB30 FOR AFTERNOON TSRA INCLUDING A 4SM VISB. SCT CIGS OUT AFTER 00Z...EVENTUALLY GIVING WAY TO HIGH LEVEL CIRRUS. WINDS WILL REMAIN GENERALLY CALM OVERNIGHT BEFORE STARTING UP OUT OF THE WEST NORTHWEST BY MID MORNING. LEE SIDE TROF WILL ONCE AGAIN VEER WINDS FURTHER NORTH THROUGH THE REMAINDER OF THE PERIOD. ELSEWHERE...MUCH THE SAME AS KCLT ABOVE AS VFR CONDITIONS WILL PREVAIL WITH THE EXCEPTION OF POSSIBLE IFR/LIFR FOG RESTRICTIONS AT KAVL...MVFR FOG RESTRICITONS AT KHKY...AND MVFR TSRA IN THE AFTERNOON FOR EACH OF THESE TWO SITES. AREAS THAT RECEIVED PRECIPITATION ON FRIDAY WILL LIKELY EXPERIENCE SOME LOWERING VISB THROUGH MORNING AS THE BOUNDARY LAYER DECOUPLES AND TEMPERATURES COOL UNDER SCT SKIES. ADDITIONALLY...MOIST PBL WILL ALLOW FOR IFR/LIFR STRATUS IN AND AROUND THE MOUNTAIN VALLEYS. OTHERWISE...CONVECTION ON SATURDAY WILL LIKELY REMAIN TIED TO THE TERRAIN...AND THE NC PIEDMONT. THUS FEATURE PROB30S FOR MVFR TSRA AT KAVL AND KHKY WHILE ONLY INCLUDING VCTS MENTION AT KGSP AND KGMU...NOT EXPECTING ANY WX AT KAND. WINDS THROUGH THE PERIOD WILL REMAIN NORTHERLY AND WILL INCREASE TO AROUND 8-10KTS WHEN MIXING IS AT ITS GREATEST DURING PEAK HEATING. OUTLOOK...ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED THIS WEEKEND...WITH THE GREATEST COVERAGE ACROSS THE MTNS AND NC PIEDMONT. RESTRICTIONS MAY OCCUR DURING TSRA AND ALSO IN THE MTN VALLEYS EACH MORNING WHERE LOW CLOUDS AND FOG MAY FORM OVER AREAS OF RECENT RAINFALL. CONFIDENCE TABLE... 05-11Z 11-17Z 17-23Z 23-05Z KCLT HIGH 100% HIGH 100% HIGH 100% LOW 56% KGSP HIGH 100% HIGH 100% HIGH 100% LOW 56% KAVL HIGH 100% HIGH 99% HIGH 100% LOW 56% KHKY HIGH 100% HIGH 100% HIGH 100% LOW 56% KGMU HIGH 100% HIGH 100% HIGH 100% LOW 56% KAND HIGH 100% HIGH 100% HIGH 100% LOW 56% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...STAARMANN NEAR TERM...CDG/SBK/WIMBERLEY SHORT TERM...JDL LONG TERM...JPT AVIATION...CDG
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
214 PM MDT SAT JUN 21 2014 .SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT ISSUED AT 210 PM MDT SAT JUN 21 2014 A BROAD NORTH/SOUTH PRE-FRONTAL SURFACE TROUGH ACROSS THE WESTERN AND CENTRAL DAKOTAS DOMINATES THE SURFACE MAP THIS AFTERNOON. THE TROUGH EXTENDS SOUTHWARD FROM A NEARLY STATIONARY LOW OVER SOUTH CENTRAL CANADA. A WEAK COLD FRONT ALSO EXTENDS SOUTHWARD FROM THIS LOW THROUGH EASTERN MONTANA AND NORTH CENTRAL WYOMING. DEWPOINT TEMPERATURES AHEAD OF THE TROUGH IN CENTRAL AND EASTERN SOUTH DAKOTA ARE IN THE MID 60S...WHILE DEWPOINTS BEHIND THE COLD FRONT DROP INTO THE MID 40S. ONLY VERY WEAK UPPER LEVEL IMPULSES ARE DISCERNABLE IN THE MOSTLY ZONAL FLOW ACROSS THE NORTHERN PLAINS TODAY. SOME WEAK CONVECTION HAS FIRED UP ALONG THE COLD FRONT IN NORTHEAST WYOMING AND EASTERN MONTANA BUT IR IMAGERY INDICATES MINIMAL VERTICAL DEVELOPMENT. A WEAKER SURFACE LOW RESIDES OVER EASTERN COLORADO...SUPORTING A MOSTLY STATIONARY EAST-WEST WARM FRONT BOUNDARY ALONG THE NEBRASKA SOUTH DAKOTA BORDER. LITTLE OR NO CONVECTIVE DEVELOPMENT HAS TAKEN PLACE ALONG THIS BOUNDARY. MORNING SOUNDINGS AT BOTH UNR AND LBF INDICATE A STRONG CAP BELOW 700 MB WITH A DRY LAYER JUST OFF THE SURFACE AND THEN UNSTABLE LAPS RATES AT MID LEVELS. TRIGGER TEMPERATURES AT BOTH LOCATIONS ARE IN THE MID 80S. THIS EVENING...THE KEY FOR LOCATING THE CONVECTIVE DEVELOPMENT THIS EVENING WILL BE THE LOCATION OF THE VERY DIFFUSE BOUNDAY COINCIDING WITH THE WESTERN DAKOTAS TROUGH. THE HRRR GUIDANCE MAINTAINS A LINE OF THUNDERSTORMS FROM THE SOUTHWEST CORNER OF SOUTH DAKOTA TO CENTRAL SOUTH DAKOTA AS WELL AS AN AREA OF POST FRONTAL STORMS OVER NORTHEAST WYOMING. THE COMBINATION OF MID LEVEL INSTABILITY...LARGE CAPE VALUES OVER 2000 J/KG AND ADEQUATE BULK SHEAR OF 30 TO 40 KTS WILL SUPPORT SUPERCELL DEVELOPMENT CAPABLE OF PRODUCING STRONG WINDS GUSTS AND LARGE HAIL. IT APPEARS AT THIS TIME THAT MOST OF THE ACTION THIS AFTERNOON WILL TAKE PLACE EAST AND SOUTH OF THE BLKHLS REGION WITH SOMEWHAT WEAKER ACTIVITY OVER NORTHEAST WYOMING. OVERNIGHT TONIGHT...THE SURFACE FRONT WILL SLOWLY SHIFT SOUTH AND EAST DURING THE LATE EVENING. STRONG TO SEVERE STORMS ARE LIKELY ALONG OR NEAR THE FRONTAL BOUNDARY AS IT CONTINUES EASTWARD INTO CENTRAL SOUTH DAKOTA BY 04Z. A WEAK UPPER LEVEL IMPULSE IS EXPECTED TO MOVE INTO NORTHEAST WYOMING AND AND A BROAD AREA OF ISENTROPIC UPGLIDE IS FORECAST TO DEVELOP OVER THE SHALLOW COOL AIR IN WESTERN SOUTH DAKOTA AND NORTHEAST WYOMING MOSTLY SOUTH OF US HWY 212 RESULTING IN A STRATIFORM PRECIP EVENT FOR AREAS STRETCHING FROM AROUND THE BLKLHS TO THE MORVR. TEMPERATURES WILL COOL INTO THE 50S TO LOWER 60S. SUNDAY...OVERCAST SKIES AND STRATIFORM PRECIP SHOULD BE ONGOING BEFORE SUN RISE IN NORTHEAST WYOMING AND THE BLKHLS AREA AND SPREAD TO THE MORVR BEFORE NOON. ISOLATED THUNDERSTORMS ARE POSSIBLE...BUT THESE SHOULD BE PRETTY WEAK. A MODERATE NORTHWEST BREEZE WILL ACCOMPANY THE LIGHT RAIN. THE LIGHT RAIN IS EXPECTED TO BEGIN TAPPERING OFF BY 00Z AS THE COOL AIRMASS PUSHES FURTHER SOUTH AND EAST. COOLER AIR WILL MOVE INTO THE NORTHERN PLAINS...WITH HIGH TEMPERATURES 10 TO 15 DEGRESS COOLER THAN TODAY...ONLY IN THE MID 60S TO UPPER 70S. SUNDAY NIGHT...DISSIPATING PRECIPITATION AND SOME LINGERING CLOUD COVER WILL KEEP TEMPERATURES FROM DROPPING BELOW THE LOWER 50S IN MOST PLACES...UPPER 40S IN NORTHEAST WYOMING AND THE BLKHLS. && .LONG TERM...MONDAY THROUGH SATURDAY ISSUED AT 210 PM MDT SAT JUN 21 2014 AN UPPER LEVEL RIDGE OVER THE NORTHERN ROCKIES WILL SLOWLY EXPAND EASTWARD MONDAY THROUGH THURSDAY. BY THURSDAY...AN UPPER LEVEL TROUGH WILL HAVE DEVELOPED OVER SOUTHWEST CANADA/NORTHWEST US. THE RESULT WILL BE WEST/NORTHWEST FLOW ALOFT EARLY IN THE PERIOD TRANSITIONING TO SOUTHWEST FLOW ALOFT BY THE END OF THE WEEK. A PARADE OF SHORTWAVES WILL BRING TSRA AT TIMES...ESPECIALLY DURING THE AFTERNOON/EVENING HOURS GIVEN SLOWLY BUILDING THERMAL RIDGE OVER THE NORTHERN PLAINS AND SUBSEQUENT SLIGHTLY HIGHER MLCIN VALUES. GFS/ECMWF ARE IN GENERAL AGREEMENT...BUT BOTH HINT AT POSSIBLE BACK DOOR COOL FRONTS TUESDAY OR WEDNESDAY FOR THE SD PLAINS GIVEN PROXIMITY OF UPPER LOW OVER HUDSON BAY. DIDN/T DEVIATE MUCH FROM GUIDANCE VALUES FOR TEMPERATURES. && .AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY ISSUED AT 210 PM MDT SAT JUN 21 2014 SCATTERED TSRA WILL CONTINUE TO DEVELOP ON THE SD PLAINS AND SPREAD EAST THROUGH THIS EVENING. ISOLATED TSRA ARE POSSIBLE OVER NORTHEAST WY INTO THE BLACK HILLS THROUGH EARLY THIS EVENING. HAIL/GUSTY WINDS ARE POSSIBLE WITH ANY STORMS INCLUDING LOCAL IFR VSBYS/CIGS... PARTICULARLY FROM SOUTHWEST THROUGH SOUTH CENTRAL SD. ANOTHER WAVE OF SHRA/TSRA WILL DEVELOP LATER TONIGHT INTO SUNDAY MORNING RESULTING IN RATHER WIDESPREAD PRECIPITATION COVERAGE ACROSS NORTHEAST WY/WESTERN SD...WITH AREAS MVFR CIGS/VSBYS IN THE STRONGEST ECHOES. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...CARPENTER LONG TERM...HELGESON AVIATION...HELGESON
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1057 AM MDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1027 AM MDT SAT JUN 21 2014 A BROAD NORTH/SOUTH PRE-FRONTAL SURFACE TROUGH ACROSS THE WESTERN DAKOTAS DOMINATES THE SURFACE MAP. THE TROUGH EXTENDS SOUTHWARD FROM A NEARLY STATIONARY LOW OVER SOUTH CENTRAL CANADA. A WEAK COLD FRONT ALSO EXTENDS SOUTHWARD FROM THIS LOW THROUGH EASTERN MONTANA AND NORTH CENTRAL WYOMING. DEWPOINT TEMPERATURES AHEAD OF THE TROUGH IN CENTRAL AND EASTERN SOUTH DAKOTA ARE IN THE MID 60S...WHILE DEWPOINTS BEHIND THE COLD FRONT DROP INTO THE MID 40S. ONLY VERY WEAK UPPER LEVEL IMPULSES ARE DISCERNIBLE IN THE MOSTLY ZONAL FLOW ACROSS THE NORTHERN PLAINS TODAY. SOME WEAK CONVECTION HAS FIRED UP ALONG THE COLD FRONT IN NORTHEAST WYOMING AND EASTERN MONTANA BUT IR IMAGERY INDICATES NO SIGNIFICANT VERTICAL DEVELOPMENT. A WEAKER SURFACE LOW RESIDES OVER EASTERN COLORADO...SUPPORTING A MOSTLY STATIONARY EAST-WEST WARM FRONT BOUNDARY ALONG THE NEBRASKA SOUTH DAKOTA BORDER. LITTLE OR NO CONVECTIVE DEVELOPMENT HAS TAKEN PLACE ALONG THIS BOUNDARY. MORNING SOUNDINGS AT BOTH UNR AND LBF INDICATE A STRONG CAP BELOW 700 MB WITH A DRY LAYER JUST OFF THE SURFACE AND THEN UNSTABLE LAPS RATES AT MID LEVELS. TRIGGER TEMPERATURES AT BOTH LOCATIONS ARE IN THE MID 80S. TODAY...THE KEY FOR LOCATING THE CONVECTIVE DEVELOPMENT THIS AFTERNOON WILL BE THE LOCATION OF THE VERY DIFFUSE BOUNDARY COINCIDING WITH THE WESTERN DAKOTAS TROUGH AT THE TIME THE TRIGGER TEMPERATURES ARE MET. THE HRRR SEEMS TO BE SHOWING A PRETTY GOOD SOLUTION FOR THIS...DEVELOPING A LINE OF THUNDERSTORMS FROM THE SOUTHWEST CORNER OF SOUTH DAKOTA TO CENTRAL SOUTH DAKOTA BETWEEN 20Z AND 21Z. AS MENTIONED IN PREVIOUS DISCUSSIONS...THE COMBINATION OF MID LEVEL INSTABILITY...LARGE CAPE VALUES OVER 2000 J/KG AND ADEQUATE BULK SHEAR OF 30 TO 40 KTS WILL SUPPORT DISCREET SUPERCELL DEVELOPMENT CAPABLE OF PRODUCING STRONG WINDS GUSTS AND LARGE HAIL. IT APPEARS AT THIS TIME THAT MOST OF THE ACTION THIS AFTERNOON WILL TAKE PLACE EAST AND SOUTH OF THE BLKHLS REGION. && .SHORT TERM...TODAY THROUGH SUNDAY NIGHT ISSUED AT 256 AM MDT SAT JUN 21 2014 UPPER LEVEL ANALYSIS HAS CLOSED LOW OVER SOUTH CENTRAL CANADA WITH NEAR ZONAL FLOW ACROSS THE NORTHERN PLAINS. SKIES ARE MOSTLY CLEAR ACROSS THE AREA AT THE MOMENT. AT THE SURFACE...DIFFUSE TROF OF LOW PRESSURE STRETCHES NORTH/SOUTH ACROSS THE WESTERN DAKOTAS WITH WEAK LOW CENTERS LOCATED IN SOUTH CENTRAL CANADA AND SOUTHEASTERN COLORADO. WARM FRONTAL BOUNDARY EXTENDS FROM THE COLORADO LOW INTO FAR SOUTH CENTRAL SOUTH DAKOTA. TEMPERATURES AT 3 AM ARE GENERALLY IN THE MID 50S TO MID 60S. WINDS ARE LIGHT. TODAY...UPPER LOW CONTINUES TO CHURN ACROSS SOUTH CENTRAL CANADA AS UPPER FLOW REMAINS NEARLY ZONAL ACROSS THE NORTHERN PLAINS. WEAK MID LEVEL ENERGY IN THIS FLOW CONTINUES TO MOVE WEST TO EAST ACROSS THE AREA. AT THE SURFACE...WEAK FRONTAL BOUNDARY ACROSS SOUTH CENTRAL SOUTH DAKOTA WILL SHIFT INTO WESTERN SOUTH DAKOTA BY MID DAY WITH SOUTHEASTERLY WINDS TRANSPORTING ADDITIONAL MOISTURE INTO THE WESTERN SOUTH DAKOTA PLAINS. VERY WARM SURFACE TEMPS...IN THE MID 70S TO UPPER 80S...COMBINED WITH INCREASING MOISTURE WILL PRODUCE VERY UNSTABLE CONDITIONS ACROSS THE SOUTH DAKOTA PLAINS EARLY THIS AFTERNOON. CAPE VALUES QUICKLY EXCEED 2000 J/KG...AND WITH DECENT SHEAR AND SURFACE FRONTAL BOUNDARY IN PLAY...STRONG TO SEVERE THUNDERSTORMS ARE LIKELY TO FORM FROM THE BLACK HILLS EAST. THE MAIN THREAT FROM ANY STORM WILL BE LARGE HAIL AND DAMAGING WIND GUSTS. TONIGHT...SURFACE FRONT WILL SLOWLY SHIFT SOUTH AND EAST DURING THE EVENING...WITH STRONG TO SEVERE STORMS CONTINUING. THE STRONGEST STORMS SHOULD PUSH EAST DURING THE EVENING WITH THE FRONTAL BOUNDARY. ADDITIONAL SHORTWAVE ENERGY WILL MOVE INTO WESTERN PARTS OF THE AREA OVERNIGHT. EXPECT SHOWERS AND STORMS TO CONTINUE ACROSS MUCH OF THE AREA THROUGH EARLY SUNDAY MORNING. TEMPERATURES WILL COOL INTO THE 50S TO LOWER 60S. SUNDAY...ZONAL FLOW CONTINUES WITH WEAK SHORTWAVE ENERGY CROSSING THE NORTHERN PLAINS. MOSTLY CLOUDY SKIES ARE EXPECTED WITH SHOWERS AND THUNDERSTORMS CONTINUING ACROSS THE AREA ON SUNDAY...WITH BEST CHANCES ACROSS NORTHEAST WYOMING AND SOUTHERN SOUTH DAKOTA. COOLER AIR WILL MOVE INTO THE NORTHERN PLAINS...WITH HIGH TEMPERATURES ONLY IN THE MID 60S TO UPPER 70S EXPECTED. && .LONG TERM...MONDAY THROUGH FRIDAY ISSUED AT 256 AM MDT SAT JUN 21 2014 UPPER LEVEL LOW PRESSURE OVER MANITOBA ON MONDAY WILL SLOWLY DROP INTO NORTHERN MINNESOTA BY MID WEEK...BEFORE PUSHING EAST BY THE END OF THE EXTENDED PERIOD. AT THE SAME TIME...AN UPPER LEVEL RIDGE WILL BUILD OVER THE NORTHERN ROCKIES AND SLOWLY SHIFT EASTWARD INTO THE NORTHERN PLAINS NEXT WEEK. THERMAL RIDGE INCREASES THROUGH THE WEEK...WITH MUCH WARMER/SUMMERLIKE TEMPERATURES TOWARD THE END OF THE WORK WEEK. HOWEVER...ANOTHER UPPER TROF PUSHES THROUGH THE ROCKIES LATE IN THE PERIOD...WHICH WILL ONCE AGAIN COOL TEMPERATURES DOWN TO BELOW SEASONAL AVERAGES FOR NEXT WEEKEND. DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS ARE EXPECTED AS A SERIES OF SHORTWAVES PASS THROUGH THE FLOW. COVERAGE BY MID WEEK SHOULD BE KEPT TO A MINIMUM AS HIGHER MID-LEVEL TEMPERATURES TEND TO KEEP MLCIN VALUES UP DURING PEAK HEATING. HOWEVER WITH THE UPPER TROF PROGGED TO PUSH TOWARD THE AREA BY LATE IN THE PERIOD...CHANCES WILL INCREASE AGAIN TOWARD NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY) ISSUED AT 1050 AM MDT SAT JUN 21 2014 VFR CONDITIONS ARE EXPECTED THROUGH EARLY THIS AFTERNOON. SCATTERED TSRA WILL THEN DEVELOP ON THE SD PLAINS AND SPREAD EAST THROUGH THIS EVENING. ISOLATED TSRA ARE POSSIBLE OVER NORTHEAST WY INTO THE BLACK HILLS THROUGH EARLY THIS EVENING. HAIL/GUSTY WINDS ARE POSSIBLE WITH ANY STORMS INCLUDING LOCAL IFR VSBYS/CIGS...PARTICULARLY FROM SOUTHWEST THROUGH SOUTH CENTRAL SD. ANOTHER WAVE OF SHRA/TSRA WILL DEVELOP LATER TONIGHT INTO SUNDAY MORNING RESULTING IN RATHER WIDESPREAD COVERAGE ACROSS NORTHEAST WY/WESTERN SD...AND AREAS MVFR CIGS/VSBYS IN THE STRONGEST ECHOES. && .HYDROLOGY... ISSUED AT 256 AM MDT SAT JUN 21 2014 FLOODING HAS SUBSIDED ACROSS THE FORECAST AREA. RIVERS AND STREAMS REMAIN HIGH...BUT HAVE RECEDED SIGNIFICANTLY OVER THE PAST FEW DAYS. THUS...ALL FLOOD WARNINGS HAVE BEEN CANCELLED OR WERE ALLOWED TO EXPIRE. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...CARPENTER SHORT TERM...15 LONG TERM...MLS AVIATION...HELGESON HYDROLOGY...MLS
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1029 AM MDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1027 AM MDT SAT JUN 21 2014 A BROAD NORTH/SOUTH PRE-FRONTAL SURFACE TROUGH ACROSS THE WESTERN DAKOTAS DOMINATES THE SURFACE MAP. THE TROUGH EXTENDS SOUTHWARD FROM A NEARLY STATIONARY LOW OVER SOUTH CENTRAL CANADA. A WEAK COLD FRONT ALSO EXTENDS SOUTHWARD FROM THIS LOW THROUGH EASTERN MONTANA AND NORTH CENTRAL WYOMING. DEWPOINT TEMPERATURES AHEAD OF THE TROUGH IN CENTRAL AND EASTERN SOUTH DAKOTA ARE IN THE MID 60S...WHILE DEWPOINTS BEHIND THE COLD FRONT DROP INTO THE MID 40S. ONLY VERY WEAK UPPER LEVEL IMPULSES ARE DISCERNABLE IN THE MOSTLY ZONAL FLOW ACROSS THE NORTHERN PLAINS TODAY. SOME WEAK CONVECTION HAS FIRED UP ALONG THE COLD FRONT IN NORTHEAST WYOMING AND EASTERN MONTANA BUT IR IMAGERY INDICATES NO SIGNIFICANT VERTICAL DEVELOPMENT. A WEAKER SURFACE LOW RESIDES OVER EASTERN COLORADO...SUPORTING A MOSTLY STATIONARY EAST-WEST WARM FRONT BOUNDARY ALONG THE NEBRASKA SOUTH DAKOTA BORDER. LITTLE OR NO CONVECTIVE DEVELOPMENT HAS TAKEN PLACE ALONG THIS BOUNDARY. MORNING SOUNDINGS AT BOTH UNR AND LBF INDICATE A STRONG CAP BELOW 700 MB WITH A DRY LAYER JUST OFF THE SURFACE AND THEN UNSTABLE LAPS RATES AT MID LEVELS. TRIGGER TEMPERATURES AT BOTH LOCATIONS ARE IN THE MID 80S. TODAY...THE KEY FOR LOCATING THE CONVECTIVE DEVELOPMENT THIS AFTERNOON WILL BE THE LOCATION OF THE VERY DIFFUSE BOUNDAY COINCIDING WITH THE WESTERN DAKOTAS TROUGH AT THE TIME THE TRIGGER TEMPERATURES ARE MET. THE HRRR SEEMS TO BE SHOWING A PRETTY GOOD SOLUTION FOR THIS...DEVELOPING A LINE OF THUNDERSTORMS FROM THE SOUTHWEST CORNER OF SOUTH DAKOTA TO CENTRAL SOUTH DAKOTA BETWEEN 20Z AND 21Z. AS MENTIONED IN PREVIOUS DISCUSSIONS...THE COMBINATION OF MID LEVEL INSTABILITY...LARGE CAPE VALUES OVER 2000 J/KG AND ADEQUATE BULK SHEAR OF 30 TO 40 KTS WILL SUPPORT DISCREET SUPERCELL DEVELOPMENT CAPABLE OF PRODUCING STRONG WINDS GUSTS AND LARGE HAIL. IT APPEARS AT THIS TIME THAT MOST OF THE ACTION THIS AFTERNOON WILL TAKE PLACE EAST AND SOUTH OF THE BLKHLS REGION. && .SHORT TERM...TODAY THROUGH SUNDAY NIGHT ISSUED AT 256 AM MDT SAT JUN 21 2014 UPPER LEVEL ANALYSIS HAS CLOSED LOW OVER SOUTH CENTRAL CANADA WITH NEAR ZONAL FLOW ACROSS THE NORTHERN PLAINS. SKIES ARE MOSTLY CLEAR ACROSS THE AREA AT THE MOMENT. AT THE SURFACE...DIFFUSE TROF OF LOW PRESSURE STRETCHES NORTH/SOUTH ACROSS THE WESTERN DAKOTAS WITH WEAK LOW CENTERS LOCATED IN SOUTH CENTRAL CANADA AND SOUTHEASTERN COLORADO. WARM FRONTAL BOUNDARY EXTENDS FROM THE COLORADO LOW INTO FAR SOUTH CENTRAL SOUTH DAKOTA. TEMPERATURES AT 3 AM ARE GENERALLY IN THE MID 50S TO MID 60S. WINDS ARE LIGHT. TODAY...UPPER LOW CONTINUES TO CHURN ACROSS SOUTH CENTRAL CANADA AS UPPER FLOW REMAINS NEARLY ZONAL ACROSS THE NORTHERN PLAINS. WEAK MID LEVEL ENERGY IN THIS FLOW CONTINUES TO MOVE WEST TO EAST ACROSS THE AREA. AT THE SURFACE...WEAK FRONTAL BOUNDARY ACROSS SOUTH CENTRAL SOUTH DAKOTA WILL SHIFT INTO WESTERN SOUTH DAKOTA BY MID DAY WITH SOUTHEASTERLY WINDS TRANSPORTING ADDITIONAL MOISTURE INTO THE WESTERN SOUTH DAKOTA PLAINS. VERY WARM SURFACE TEMPS...IN THE MID 70S TO UPPER 80S...COMBINED WITH INCREASING MOISTURE WILL PRODUCE VERY UNSTABLE CONDITIONS ACROSS THE SOUTH DAKOTA PLAINS EARLY THIS AFTERNOON. CAPE VALUES QUICKLY EXCEED 2000 J/KG...AND WITH DECENT SHEAR AND SURFACE FRONTAL BOUNDARY IN PLAY...STRONG TO SEVERE THUNDERSTORMS ARE LIKELY TO FORM FROM THE BLACK HILLS EAST. THE MAIN THREAT FROM ANY STORM WILL BE LARGE HAIL AND DAMAGING WIND GUSTS. TONIGHT...SURFACE FRONT WILL SLOWLY SHIFT SOUTH AND EAST DURING THE EVENING...WITH STRONG TO SEVERE STORMS CONTINUING. THE STRONGEST STORMS SHOULD PUSH EAST DURING THE EVENING WITH THE FRONTAL BOUNDARY. ADDITIONAL SHORTWAVE ENERGY WILL MOVE INTO WESTERN PARTS OF THE AREA OVERNIGHT. EXPECT SHOWERS AND STORMS TO CONTINUE ACROSS MUCH OF THE AREA THROUGH EARLY SUNDAY MORNING. TEMPERATURES WILL COOL INTO THE 50S TO LOWER 60S. SUNDAY...ZONAL FLOW CONTINUES WITH WEAK SHORTWAVE ENERGY CROSSING THE NORTHERN PLAINS. MOSTLY CLOUDY SKIES ARE EXPECTED WITH SHOWERS AND THUNDERSTORMS CONTINUING ACROSS THE AREA ON SUNDAY...WITH BEST CHANCES ACROSS NORTHEAST WYOMING AND SOUTHERN SOUTH DAKOTA. COOLER AIR WILL MOVE INTO THE NORTHERN PLAINS...WITH HIGH TEMPERATURES ONLY IN THE MID 60S TO UPPER 70S EXPECTED. && .LONG TERM...MONDAY THROUGH FRIDAY ISSUED AT 256 AM MDT SAT JUN 21 2014 UPPER LEVEL LOW PRESSURE OVER MANITOBA ON MONDAY WILL SLOWLY DROP INTO NORTHERN MINNESOTA BY MID WEEK...BEFORE PUSHING EAST BY THE END OF THE EXTENDED PERIOD. AT THE SAME TIME...AN UPPER LEVEL RIDGE WILL BUILD OVER THE NORTHERN ROCKIES AND SLOWLY SHIFT EASTWARD INTO THE NORTHERN PLAINS NEXT WEEK. THERMAL RIDGE INCREASES THROUGH THE WEEK...WITH MUCH WARMER/SUMMERLIKE TEMPERATURES TOWARD THE END OF THE WORK WEEK. HOWEVER...ANOTHER UPPER TROF PUSHES THROUGH THE ROCKIES LATE IN THE PERIOD...WHICH WILL ONCE AGAIN COOL TEMPERATURES DOWN TO BELOW SEASONAL AVERAGES FOR NEXT WEEKEND. DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS ARE EXPECTED AS A SERIES OF SHORTWAVES PASS THROUGH THE FLOW. COVERAGE BY MID WEEK SHOULD BE KEPT TO A MINIMUM AS HIGHER MID-LEVEL TEMPERATURES TEND TO KEEP MLCIN VALUES UP DURING PEAK HEATING. HOWEVER WITH THE UPPER TROF PROGGED TO PUSH TOWARD THE AREA BY LATE IN THE PERIOD...CHANCES WILL INCREASE AGAIN TOWARD NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY) ISSUED AT 1027 AM MDT SAT JUN 21 2014 VFR CONDITIONS THROUGH THIS MORNING. EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP THIS AFTERNOON AND CONTINUE OVERNIGHT. STRONGER STORMS WILL HAVE GUSTY WINDS...HAIL...AND LOCAL IFR CIGS/VSBYS. && .HYDROLOGY... ISSUED AT 256 AM MDT SAT JUN 21 2014 FLOODING HAS SUBSIDED ACROSS THE FORECAST AREA. RIVERS AND STREAMS REMAIN HIGH...BUT HAVE RECEDED SIGNIFICANTLY OVER THE PAST FEW DAYS. THUS...ALL FLOOD WARNINGS HAVE BEEN CANCELLED OR WERE ALLOWED TO EXPIRE. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...CARPENTER SHORT TERM...15 LONG TERM...MLS AVIATION...MLS HYDROLOGY...MLS
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
847 AM CDT SAT JUN 21 2014 .MESOSCALE UPDATE... SURFACE FRONT JUST OUR NORTH WITH SURFACE DEWPOINTS AROUND 70 ACROSS KENTUCKY AND LOWER 70S IN MOST OF MIDDLE TENNESSEE. CONVECTION CURRENTLY FIRING IN KENTUCKY NEARING LAKE CUMBERLAND WILL DROP DOWN INTO THE UPPER CUMBERLAND AREA NEXT HOUR OR TWO. LATEST RUC RUN HAS MUCH DRIER AIR THROUGH THE MID LEVELS WORKING DOWN ACROSS MOST OF KENTUCKY BY 16Z. THIS DRIER AIR IN THE MID LEVELS WILL WORK SOUTHWARD AS WE GO THROUGH THE DAY WHILE SURFACE DEWPOINTS REMAIN AROUND 70. THINK NORTHWEST MIDDLE TENNESSEE WILL HAVE THE LEAST CHANCE OF GETTING CONVECTION THIS MORNING WITH CONVECTION CONFINED MAINLY TO THE EASTERN MIDDLE TENNESSEE AND PLATEAU DURING THE AFTERNOON. TEMPS LOOK ON TRACK. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BOYD 01
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
533 AM CDT SAT JUN 21 2014 .UPDATE...FOR 12Z AVIATION DISCUSSION. && .AVIATION...12Z AVIATION DISCUSSION. SOME MVFR TO IFR FOG MAY PERSIST THRU 21/14Z CKV...OTHERWISE PER DIURNAL HEATING INFLUENCES...VFR SCT CU...SCT/BKN CI...THRU 22/02Z. DESPITE DRIER AIR TRYING TO WORK INTO MID STATE...SHORT RANGE MODELS SHOWING BEST POTENTIAL OF ISO/SCT SHWR/TSTM ACTIVITY CSV 21/17Z-22/02Z PER DIURNAL INFLUENCES ALSO... AND WITH ACTUAL LOCATION UNCERTAINTY DEVELOPMENT...MENTIONED VCTS. SCT/BKN CI POSSIBLE AFTER 22/02Z...WITH MVFR FOG FORMATION CKV/CSV PER LOW LEVEL MOISTURE POOLING POTENTIAL...LIGHT WINDS...AND CLR SKIES AFTER 22/08Z. NWLY SFC WINDS AROUND 5KT OR LESS EXPECTED THRU 22/12Z ALSO. && .PREV DISCUSSION.../ISSUED 344 AM CDT SAT JUN 21 2014/ DISCUSSION... HELLO FOLKS....SUMMERTIME BEGINS THIS MORNING AT 551 AM...ENJOY! AND NOW ON TO THE WEATHER....... NW FLOW ALOFT IS IN PLACE AS THE UPPER HIGH NOW RESIDES OVER THE NORTHERN GULF AND IS RATHER WEAK. IN THE LOWER LEVELS...WEAK HIGH PRESSURE IS IN CONTROL. LOW LEVEL FLOW WILL GRAVITATE TOWARD A DRIER NORTHERLY FLOW BY AFTERNOON. CONVECTIVE CHARTS SHOW THE BETTER CAP EROSION ACROSS THE SOUTH WITH APPRECIABLE CAPE THERE AS WELL. THE PLAN FOR TODAY WILL BE TO CARRY A SLIGHT CHANCE OF SHOWERS AND TSTMS NORTH IN THE MORNING. ELSEWHERE...WILL CARRY THE LOW POPS THROUGH THE DAY. HRRR SHOWING SOME DEVELOPMENT BY 17Z OR SO. OTW...THE DRIER AIR WILL WIN OUT TOWARD EVENING. FOR TONIGHT AND SUNDAY...LITTLE OR NO POPS WILL BE INCLUDED. PCLDY TO MOSTLY CLEAR SKIES ARE EXPECTED FOR SUNDAY INTO SUNDAY NT. THE NEXT CHANCE OF SHOWERS AND TSTMS WILL BE ON MONDAY. AT THAT TIME...LOW LEVEL FLOW WILL BECOME MORE SOUTHERLY AND BRING A RETURN OF MOISTURE AND MORE FAVORABLE CONVECTIVE PARAMETERS. RAIN CHANCES FOR SUNDAY WILL STILL BE ON THE LOW SIDE AS THE BETTER DYNAMICS RESIDE TO OUR NW. AS FOR THE NEAR TERM TEMPS...STILL LOOKING AT ABOVE NORMAL VALUES. HOWEVER...OVERNIGHT LOWS THE NEXT FEW OVERNIGHTS WILL DROP INTO THE MID TO UPPER 60S AS THE SOMEWHAT DRIER AIR PREVAILS. VERSUS THE GUIDANCE...VERY LITTLE DEVIATION THIS ROUND. IN THE EXT FCST...THE GFS SHOWS A NICELY STACKED STORM SYSTEM ON APPROACH FOR TUESDAY. EURO SOLUTION IS ABOUT 24 HOURS LATER. SFC LOW LOOKS AS THOUGH IT WILL TRACK ACROSS NORTHERN MIDDLE TN ON WED AFTERNOON. AT THAT TIME...CAPE VALUES LOOK UNIMPRESSIVE AND THE SYSTEM APPEARS TO BE MORE OF A RAINFALL EVENT. CAPES ARE HIGHER TO OUR SOUTH WHERE THE BETTER MID LEVEL JET RESIDES. AT ANY RATE...CANNOT RULE OUT AN INCH OR SO OF RAINFALL FOR TUESDAY THROUGH WEDNESDAY. FOLLOWING THE EXIT OF THE MID WEEK STORM SYSTEM. WEAK RIDGING WILL ATTEMPT TO REESTABLISH ITSELF. HOWEVER...BOTH THE RESIDUAL AND SOUTHERLY FLOW INDUCED MOISTURE WILL UNDERCUT ANY RIDGING THAT DEVELOPS AND CONTINUE TO PROVIDE LOW CHANCES OF SHOWERS AND TSTMS FOR THU AND FRI. FOR THE EXT TEMPS...VALUES WILL CONTINUE TO RUN A FEW DEGREES ABOVE NORMAL. A SLIGHT UNDERCUT ON MAX TEMPS WILL BE UTILIZED AS 850 MB TEMPS ARE KEPT WITHIN THE 16C TO 18C RANGE AND A LITTLE MORE IN THE WAY OF CLOUDINESS WILL EXIST. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
344 AM CDT SAT JUN 21 2014 .DISCUSSION... HELLO FOLKS....SUMMERTIME BEGINS THIS MORNING AT 551 AM...ENJOY! AND NOW ON TO THE WEATHER....... NW FLOW ALOFT IS IN PLACE AS THE UPPER HIGH NOW RESIDES OVER THE NORTHERN GULF AND IS RATHER WEAK. IN THE LOWER LEVELS...WEAK HIGH PRESSURE IS IN CONTROL. LOW LEVEL FLOW WILL GRAVITATE TOWARD A DRIER NORTHERLY FLOW BY AFTERNOON. CONVECTIVE CHARTS SHOW THE BETTER CAP EROSION ACROSS THE SOUTH WITH APPRECIABLE CAPE THERE AS WELL. THE PLAN FOR TODAY WILL BE TO CARRY A SLIGHT CHANCE OF SHOWERS AND TSTMS NORTH IN THE MORNING. ELSEWHERE...WILL CARRY THE LOW POPS THROUGH THE DAY. HRRR SHOWING SOME DEVELOPMENT BY 17Z OR SO. OTW...THE DRIER AIR WILL WIN OUT TOWARD EVENING. FOR TONIGHT AND SUNDAY...LITTLE OR NO POPS WILL BE INCLUDED. PCLDY TO MOSTLY CLEAR SKIES ARE EXPECTED FOR SUNDAY INTO SUNDAY NT. THE NEXT CHANCE OF SHOWERS AND TSTMS WILL BE ON MONDAY. AT THAT TIME...LOW LEVEL FLOW WILL BECOME MORE SOUTHERLY AND BRING A RETURN OF MOISTURE AND MORE FAVORABLE CONVECTIVE PARAMETERS. RAIN CHANCES FOR SUNDAY WILL STILL BE ON THE LOW SIDE AS THE BETTER DYNAMICS RESIDE TO OUR NW. AS FOR THE NEAR TERM TEMPS...STILL LOOKING AT ABOVE NORMAL VALUES. HOWEVER...OVERNIGHT LOWS THE NEXT FEW OVERNIGHTS WILL DROP INTO THE MID TO UPPER 60S AS THE SOMEWHAT DRIER AIR PREVAILS. VERSUS THE GUIDANCE...VERY LITTLE DEVIATION THIS ROUND. IN THE EXT FCST...THE GFS SHOWS A NICELY STACKED STORM SYSTEM ON APPROACH FOR TUESDAY. EURO SOLUTION IS ABOUT 24 HOURS LATER. SFC LOW LOOKS AS THOUGH IT WILL TRACK ACROSS NORTHERN MIDDLE TN ON WED AFTERNOON. AT THAT TIME...CAPE VALUES LOOK UNIMPRESSIVE AND THE SYSTEM APPEARS TO BE MORE OF A RAINFALL EVENT. CAPES ARE HIGHER TO OUR SOUTH WHERE THE BETTER MID LEVEL JET RESIDES. AT ANY RATE...CANNOT RULE OUT AN INCH OR SO OF RAINFALL FOR TUESDAY THROUGH WEDNESDAY. FOLLOWING THE EXIT OF THE MID WEEK STORM SYSTEM. WEAK RIDGING WILL ATTEMPT TO REESTABLISH ITSELF. HOWEVER...BOTH THE RESIDUAL AND SOUTHERLY FLOW INDUCED MOISTURE WILL UNDERCUT ANY RIDGING THAT DEVELOPS AND CONTINUE TO PROVIDE LOW CHANCES OF SHOWERS AND TSTMS FOR THU AND FRI. FOR THE EXT TEMPS...VALUES WILL CONTINUE TO RUN A FEW DEGREES ABOVE NORMAL. A SLIGHT UNDERCUT ON MAX TEMPS WILL BE UTILIZED AS 850 MB TEMPS ARE KEPT WITHIN THE 16C TO 18C RANGE AND A LITTLE MORE IN THE WAY OF CLOUDINESS WILL EXIST. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 91 68 93 69 / 20 10 10 10 CLARKSVILLE 91 66 93 67 / 10 10 10 10 CROSSVILLE 84 64 87 63 / 20 10 10 10 COLUMBIA 92 68 93 70 / 20 10 10 10 LAWRENCEBURG 92 67 92 69 / 20 10 10 10 WAVERLY 91 66 93 68 / 20 10 10 10 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
212 PM CDT Sat Jun 21 2014 .DISCUSSION... A well defined Mexican moisture tap is still evident on water vapor imagery with embedded shrtwv trof/s, one of which is lifting out the area while another model depicted shrtwv trof follows and in part is responsible for renewed SHRA/TSRA. The area where SHRA/TSRA have been occurring is area co-located where 9h-85h mstr flux has persisted and PWs are near 1.75" per GEFS (about 2.5 standard deviations above normal). The RUC13 show this area of moisture flux redeveloping to the n into the n-ne PB and thus we would not be surprised to SHRA/TSRA develop into the n-ne these next few hrs. Heavy rain is main concern and local flooding/flash flooding is possible. Mid level ridge will slowly builds in from the w and serve to push the general mid level trof/moisture axis that has been over the area to the e resulting in a decreased chance of rain and an increase in temperatures. Still there are some opportunities for precip. For Sunday PoPs will generally be confined to the mtns where very steep LR/s of 8-9 c/km are to be coincident with sfc dwpnts in the m40-50 along e slopes, flow will be upslope, and CINH will be a non-issue in/near elevated heat sources. Meanwhile Sunday night storms may near the far NW CWFA with shrtwv trof in NW flow aloft. On Monday NAM12/ECMWF better depicts a shrtwv trof in the NW flow and develops storms by mid/late afternoon in E-SE NM and then in PB after 21Z. Development may be enhanced by a boundary from previous convection and/or its own cold pool. Timing will be important, if it does come thru early then there won`t be much concern for precip into the evening. Tue models hint at tstms from the mtns into E-SE NM where moist se low level flow and secondary mid level theta-e ridge are expected to be. ECMWF wants light up the mtns again Thur/Fri, while the GFS confines precip moreso to the Davis mtns. As frequently is the case for the mtns the development is tied to the mid level theta-e ridge axis and based on consensus of data the Davis mtns are favored over the GDP mtns. A mid level trof is progged to push in to the n Friday, which may advect drier air ewd. Through the extended part of the fcst the GFS is much warmer than ECMWF in part due to its more veered/stronger wly winds which aids thermal ridge/dry air. Climatology certainly favors the GFS and with warm temperatures already in forecast with probably use a blender approach to catch general trends. && .PRELIMINARY POINT TEMPS/POPS... ANDREWS TX 68 96 69 95 / 10 10 10 30 BIG SPRING TX 69 93 72 93 / 20 10 10 20 CARLSBAD NM 67 101 72 101 / 10 20 20 10 DRYDEN TX 75 97 74 102 / 20 10 10 10 FORT STOCKTON TX 71 96 72 99 / 10 10 10 10 GUADALUPE PASS TX 70 99 70 96 / 10 20 20 10 HOBBS NM 66 95 67 92 / 10 10 10 30 MARFA TX 59 95 60 96 / 20 10 10 10 MIDLAND INTL AIRPORT TX 71 95 72 94 / 10 10 10 20 ODESSA TX 70 94 70 94 / 10 10 10 20 WINK TX 71 100 73 100 / 10 10 10 20 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
916 AM EDT SAT JUN 21 2014 .SYNOPSIS... LOW PRESSURE OVER OHIO WILL MOVE SOUTHEAST ALONG A FRONT INTO SOUTHEAST VIRGINIA BY THIS EVENING. HIGH PRESSURE WILL COVER THE NORTHEAST AND MID ATLANTIC REGION TONIGHT AND SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 912 AM EDT SATURDAY... MORNING SHOWERS OVER THE PIEDMONT ARE EXITING THE AREA WHILE A NEW BATCH IS ENTERING THE WESTERN SLOPES OF RNK CWA. ADJUSTED POPS TO REFLECT RADAR TREND THROUGH THE REST OF THE MORNING. MODELS ARE STILL BULLISH FOR SHOWERS THIS AFTERNOON...ESPECIALLY ACROSS THE PIEDMONT. 9AM RAP INSTABILITIES SHOWING 400-800 CAPE VALUES ACROSS THE FOOTHILLS. IF THE SUN CAN PENETRATE THICK MORNING CLOUDS...FORECAST LOOKS GOOD FOR HIGH POPS IN THE EAST THIS AFTERNOON. LEFT THE MAJORITY OF THE AFTERNOON FORECAST AS IS..JUST ADJUSTED TIMING THROUGH NOON. AS OF 400 AM EDT SATURDAY... VERY LITTLE CHANGE IN THE OVERALL WEATHER PATTERN IS EXPECTED TODAY AND TONIGHT. A WAVY STATIONARY FRONT TRAILED FROM THE OHIO VALLEY INTO NORTH CAROLINA. LOW LEVEL MOISTURE AND SURFACE DEW POINTS HOLDING IN THE MID TO UPPER 60S WILL RESULT IN DECENT MIXED LAYER CAPES WITH ANY HEATING TODAY. AMOUNT OF SUN THIS MORNING IS CHALLENGING. WEAK CAPPING...AT LEAST NOT WARM ENOUGH AT MID LEVELS THAT CAP CAN BE OVERCOME WITH HEATING...CONVERGENCE ALONG THE BOUNDARY AND CAPES AROUND 1500 J/KG SUPPORT OTHER AFTERNOON AND EVENING WITH SCATTERED SHOWERS AND THUNDERSTORMS. WILL ALIGN HIGHEST PROBABILITY OF PRECIPITATION ALONG THE BOUNDARY...MAINLY FROM THE BLUE RIDGE NORTH OF ROANOKE INTO MUCH OF THE PIEDMONT THIS AFTERNOON...BUT NO AREA IS FREE FROM ANY RAIN CHANCE TODAY. PRECIPITABLE WATER VALUES ARE FORECAST TO BE CLOSE TO 2.0 INCHES IN THE FAR SOUTHEAST CORNER OF THE FORECAST AREA THIS AFTERNOON. WILL MENTION HEAVY RAIN THREAT IN THE FORECAST AND HAZARDOUS WEATHER OUTLOOK. SURFACE LOW PRESSURE IN SOUTHEAST VIRGINIA BY THIS EVENING WILL BRING LOW LEVEL WINDS AROUND TO THE NORTH AND NORTHEAST. THIS MAY BRIEFLY BRING RELATIVELY MORE STABLE AIR INTO THE REGION OVERNIGHT. THIS SHOULD LIMIT THE COVERAGE OF SHOWERS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 305 AM EDT SATURDAY... RELATIVELY LITTLE CHANGE IN AIRMASS ANTICIPATED DURING THE SHORT TERM PERIOD WITH BAROCLINIC ZONE REMAINING TO THE NORTH OF THE BLACKSBURG FORECAST AREA. DAILY TEMPERATURE CHANGES WILL LARGELY BE INFLUENCED BY EXTENT OF CLOUD COVER AND IMPACT OF ANY PASSING SHOWERS/THUNDERSTORMS. ATMOSPHERE OVER THE MID APPALACHIAN AND MID ATLANTIC STATES WILL REMAIN MAINLY UNCAPPED...BUT WITH MID LEVEL LAPSE RATES RATHER ANEMIC. WITH LACK OF ANY SIGNIFICANT SHORT WAVE FORCING...THREAT OF PRECIPITATION WILL BE DIURNALLY DRIVEN...AND NOT AS STRONG AS THE PAST SEVERAL DAYS. EXPECT TO SEE REDEVELOPMENT OF SHOWERS/THUNDERSTORMS BY LATE SUNDAY MORNING/EARLY AFTERNOON ALONG/NEAR THE SPINE OF THE BLUE RIDGE AS WEAK CONFLUENCE SETS UP DUE TO LIGHT NORTHEAST TO EAST WINDS EAST OF THE MOUNTAINS...WITH MORE OF A WESTERLY COMPONENT FURTHER WEST. COMBINATION OF LOW LEVEL CONFLUENCE AND DIFFERENTIAL HEATING SHOULD BE SUFFICIENT TO SUPPORT AT LEAST WIDELY SCATTERED ACTIVITY...WHICH WILL LIKELY DRIFT EAST OUT OVER THE FOOTHILLS BY MID-LATE AFTERNOON BEFORE GRADUALLY DISSIPATING WITH LOSS OF DAYTIME HEATING ON SUNDAY EVENING. SLOWLY RISING HEIGHTS AS UPPER RIDGE BEGINS TO BUILD NORTH FROM OFF THE SOUTHEAST COAST...WITH UPPER TROFFING DEVELOPING UPSTREAM OVER THE MISSISSIPPI VALLEY...WILL SUPPORT SURFACE WINDS OVER THE BLACKSBURG AREA TO GRADUALLY VEER INTO THE SOUTHEAST ON MONDAY... AGAIN SUPPORTING THE BEST THREAT FOR WIDELY SCATTERED/SCATTERED SHOWER/THUNDERSTORM REDEVELOPMENT DURING THE LATE MORNING/EARLY AFTERNOON ALONG AND NEAR THE BLUE RIDGE. WITH MID LEVEL LAPSE RATES REMAINING WEAK...THREAT FOR SEVERE WEATHER AGAIN APPEARS TO BE MINIMAL AT THE PRESENT TIME. MOS GUIDANCE SIMILAR THROUGH THE PERIOD AND GENERALLY ACCEPTED WITH DAYTIME HIGHS MAINLY IN THE 80S...WITH 70S CONFINED TO THE HIGHER ELEVATIONS...AND WITH OVERNIGHT LOWS GENERALLY BE IN THE 60S... WITH SOME UPPER 50S POSSIBLE IN THE DEEPER MOUNTAIN VALLEYS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 140 PM EDT FRIDAY... THIS PERIOD OF THE FORECAST WILL STAY SIMILAR TO THE PREVIOUS FORECAST. THE AIRMASS OVERALL STAYS ON THE WARM/HUMID SIDE WITH 5H RIDGE OVER THE SOUTHEAST. ONE TROUGH AND ASSOCIATED FRONT WORKS ACROSS THE MIDWEST INTO THE MID ATLANTIC BY WEDNESDAY. THIS WILL NUDGE OUR CHANCE OF STORMS UP MIDWEEK. THE FRONT SITUATES ITSELF MORE IN A WEST TO EAST ORIENTATION THU-FRI WHICH WILL KEEP THREAT OF SHOWERS AND STORMS AROUND. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... AS OF 745 AM EDT SATURDAY... WAVY WARM FRONT EXTENDED FROM THE MARYLAND PANHANDLE TO NORTHEAST NORTH CAROLINA. ISOLATED LIGHT SHOWERS WERE OVER THE MOUNTAINS ALONG WITH IFR TO MVFR CEILINGS. WATER VAPOR LOOP SHOWED A SHORT WAVE OVER INDIANA AND OHIO. MODELS MOVE THIS FEATURE ACROSS THE FORECAST AREA THIS MORNING. SCATTERED THUNDERSTORMS WILL DEVELOP AGAIN THIS AFTERNOON...BUT THE BIGGEST QUESTION IS WHERE. AM LEAVING THUNDERSTORMS OUT OF TAFS...EXCEPT FOR KDAN...FOR NOW UNTIL IT IS CLEAR WHERE STORMS WILL DEVELOP TODAY MVFR FOG WILL SLOWLY DISSIPATE. CONDITIONS MAY NOT IMPROVE TO VFR UNTIL AFTER 16Z/NOON. CEILINGS AND VISIBILITY OUTSIDE OF SHOWERS AND THUNDERSTORMS WILL THEN BE VFR FOR THE REST OF THE DAY. EXTENDED AVIATION DISCUSSION... CHANCE OF SHOWERS AND THUNDERSTORMS IS LESS ON SUNDAY. DEEPER MOISTURE RETURNS NORTH...WITH BETTER COVERAGE OF AFTERNOON/EVENING STORMS ON MONDAY AHEAD OF ANOTHER UPPER TROF AND FRONT TO THE WEST. THIS BOUNDARY WILL GET CLOSER TUESDAY INTO WEDNESDAY WITH AT LEAST DIURNAL DAILY ROUNDS OF SHOWERS AND STORMS LIKELY TUESDAY INTO WEDNESDAY INCLUDING PERIODS OF MVFR/IFR. AREAS OF IFR FOG REMAIN POSSIBLE EACH LATE NIGHT/EARLY MORNING... PARTICULARLY IN AREAS THAT SEE RAIN THE PREVIOUS AFTERNOON. THE MOST OPTIMAL FLIGHT CONDITIONS EACH DAY SHOULD BE IN THE MID TO LATE MORNING AFTER FOG/LOW CLOUDS LIFT AND BURN OFF...AND BEFORE AFTERNOON CONVECTION REDEVELOPS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/RCS SHORT TERM...WERT LONG TERM...WP AVIATION...AMS/JH/RCS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1006 PM CDT SUN JUN 22 2014 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE AND NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 954 PM CDT SUN JUN 22 2014 ISOLATED TO SCATTERED SHOWERS CONTINUE OVER CENTRAL AND NORTH CENTRAL WI AS FIRST OF A FEW SHORT WAVES MOVE THROUGH. GIVEN VERY LIGHT WINDS ALOFT/SEE 00Z GRB SOUNDING...SHOWER MOVEMENT RATHER SLOW. THUS LOCALLY HEAVY RAIN POSSIBLE WITH THE SHOWERS AND STORMS. HAVE FOLLOWED HRRR FOR PCPN COVERAGE THROUGH THE NIGHT INTO MON MORNING AS SEEMS TO BE CAPTURING CURRENT ACTIVITY BETTER THAN OTHERS. TREND OF HRRR IS TO INCREASE ACTIVITY AFTER MIDNIGHT OVER CENTRAL AND NORTHEAST WI. HAVE DECIDED TO GO WITH ISOLD TO SCATTERED WORDING INTO MON MORNING...AND BACK DOWN TO LIKELY POPS PER COORDINATION WITH SURROUNDING OFFICES. SPS ISSUED AS EAST WINDS OFF LAKE MI LEADING TO FOG AT LAKESHORE. && .SYNOPSIS... ISSUED AT 300 PM CDT SUN JUN 22 2014 COOL WITH ANOTHER WIDESPREAD SOAKING RAIN LATE TONIGHT AND TOMORROW. MODEST BAND OF WESTERLIES WL REMAIN OVER THE NRN CONUS DURING THE PERIOD. THE FLOW ACROSS THE CONUS WL UNDERGO MODEST CHANGES DURING THE FCST PERIOD...MOST OF WHICH WL BE IN RESPONSE TO DEVELOPMENTS AT HIGHER LATITUDES. TROFFING DEVELOPING OVER ERN CANADA WL CAUSE HEIGHTS TO FALL A BIT IN THE ERN CONUS EARLY IN THE WEEK. THAT SHOULD ALLOW CANADIAN HIGH TO SLIDE SWD...AND PUSH SOME OF THE MOISTURE OUT OF THE AREA. THEN LATER IN THE PERIOD...STG PAC JET/UPR TROF DIGGING TOWARD THE PAC NW WL CAUSE RIDGING TO DEVELOP OVER THE GREAT LAKES RGN. THIS IS STILL A WET PATTERN...WITH ABV TO MUCH ABV NORMAL PCPN AMNTS EXPECTED FOR THE PERIOD. BUT ONCE THE ERN CANADA TROF BEGINS TO DEVELOP...HIGH PRESSURE WL BUILD SWD TOWARD THE RGN. WHILE THE DRIER AIR WITH THE HIGH MAY NOT BE ABLE TO TOTALLY SHUT DOWN THE PCPN...PCPN EVENTS DURING THE MIDDLE TO LATTER PART OF THE WK SHOULD BE MORE IN THE FORM OF SCT SHRA RATHER THAN WIDESPREAD RAINS. TEMPS WL BE COOL TOMORROW DUE TO PCPN...THEN SHOULD REMAIN NR OR A LITTLE BLO NORMAL FOR THE WORK WEEK BEFORE WARMING TO ABV NORMAL LEVELS AS THE UPR RIDGE STARTS TO BUILD OVER THE AREA NEXT WEEKEND. && .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 300 PM CDT SUN JUN 22 2014 MAIN CONCERN IS PCPN POTENTIAL THE NEXT 24 HRS. BAND OF SHRA/TSRA OVER WRN WI NOW HANDLED POORLY BY THE MODELS. IT SHOULD WEAKEN AS IT WORKS EWD...BUT NEED TO BRING POPS INTO THE AREA LATE TDA TO ACCOUNT FOR IT. BY THE TIME IT WEAKENS...SLY FLOW AT 850 MB WL BE IN PLACE AND MID-LVL SHRTWV WL BE APPROACHING...SO DON/T THINK IT WL BE WISE TO TRY AND WORK IN A TOTALY DRY PERIOD BEFORE THE MAIN SYSTEM ARRIVES. SYSTEM PROGGED TO CROSS THE AREA TOMORROW STILL HAS THE LOOK OF A HEAVY RAIN PRODUCER. SHRTWV AT 500 MB IS NOT AS DEFINED AS WITH A CLASSIC SHARS SYSTEM...BUT 700 MB SHRTWV IS PRETTY SHARP AND ALMOST CLOSED AS IT CROSSES THE AREA. PREFER SLIGHTLY SLOWER MVMT AS PROGGED BY THE ECMWF. TOOK MON POPS UP TO CATEGORICAL AND KEPT HVY RAIN ATTRIBUTE IN THE GRIDS. DID TWEAK POPS DOWN ACRS THE FAR W DURING THE LATE AFTN AS SYSTEM SHOULD BE STARTING TO PULL OUT BY THEN. BASED ON ECMWF...MOST LIKELY AREA TO GET HEAVY RAINS WOULD SEEM TO BE C-EC WI. THIS IS THE SAME AREA THAT GOT THE BULK OF THE RAIN DURING THE PAST WEEK. WILL ISSUE ESF FOR THIS AREA TO RAISE AWARNESS ANOTHER NOTCH. THIS WL ALLOW SUBSEQUENT SHIFTS TO SEE WHAT THE CONVECTION NOW HEADING IN FM THE W PRODUCES IN THE WAY OF RAINFALL BEFORE WE JUMP INTO A WATCH. WENT WITH BLEND OF GUID FOR TEMPS TNGT...THEN HELD TEMPS DOWN ON MON DUE TO THE EXPECTED RAINFALL. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 300 PM CDT SUN JUN 22 2014 CONTINUED UNSETTLED WEATHER IS EXPECTED INTO THE WEEKEND. TRIED TO FIND AN EXTENDED PERIOD OF TIME WHERE THINGS DRIED OUT EVERYWHERE AND THE WEATHER WAS MORE SUMMER-LIKE...BUT COULDNT NARROW INTO ANYTHING SPECIFIC. SO CONTINUED CHANCE FOR SHOWERS AND THUNDERSTORMS FOR THE LONG TERM. WEIGHTED FCST TOWARDS 12Z GFS/ECMWF AS THEY SEEMED TO BE MOST CONSISTENT FROM RUN TO RUN. LOW PRESSURE SYSTEM WILL BE EXITING THE AREA MONDAY NIGHT. BEST CHANCE WILL BE CONFINED TO THE EAST BEFORE MIDNIGHT. WAS TEMPTED TO REMOVE ALL POPS AFTER MIDNIGHT AS THE SYSTEM FINALLY PULLS AWAY...HOWEVER WILL STILL HAVE UPPER LEVEL TROUGH AND RRQ OF JET OVER THE GREAT LAKES REGION. LOWERED POPS AND DRIED OUT CENTRAL WISCONSIN...BUT DONT FEEL COMFORTABLE REMOVING CHANCES IN NORTH AND EAST ALL TOGETHER. AREAS OF FOG SHOULD DEVELOP LATE MONDAY NIGHT AS WELL. NEXT FEATURE TO FOCUS IS THE FRONT SAGGING SOUTH THROUGH THE CWA ON TUESDAY. STILL SOME TIMING ISSUES WITH THE FRONTAL PASSAGE. FAVORED THE GFS ENSEMBLE MEAN...AS IT SEEMED TO BE A GOOD COMPROMISE BETWEEN THE MODELS. FRONT SHOULD MOVE INTO NORTHERN WISCONSIN TUESDAY MIDDAY AND THEN MOVE SOUTH THROUGH THE AFTERNOON...BRINGING WITH IT A CHANCE FOR SHOWERS AND THUNDERSTORMS. BEST CHANCE FOR PRECIP WILL BE WITH THIS FRONT...HOWEVER HAD TO BROAD BRUSH THE POPS DUE TO THE NOTED TIMING DIFFERENCES. MODELS HAVE BEEN TRENDING SLOWER WITH THE FRONT...SO WAS ABLE TO INCREASE HIGH TEMPS ON TUESDAY. NOT TOO EXCITED ABOUT ANY STRONG OR SEVERE STORMS...AS INSTABILITY AND SHEAR WILL BE MARGINAL. STILL WORTH WATCHING HOWEVER...AS DEWPOINTS AND TEMPS ON TUESDAY KEEP CREEPING UP ON GUIDANCE AND FRONT WILL BE CROSSING THE AREA. THE FRONT SHOULD CONTINUE TO SAG SOUTHWARD TUESDAY NIGHT AND WEDNESDAY AS CANADIAN HIGH PRESSURE BUILDS INTO NORTHEAST WISCONSIN. LOWERED RAIN CHANCES ACROSS MUCH OF THE AREA WEDNESDAY AND WEDNESDAY NIGHT SLIGHTLY...HOWEVER WASNT ABLE TO PULL POPS COMPLETELY AS MODELS STILL HAVE SCATTERED SHOWERS AROUND AS WEAK IMPULSES MOVE THROUGH THE MEAN ZONAL FLOW. GIVEN THE AMOUNT OF AVAILABLE MOISTURE...WOULDNT TAKE A LOT TO SQUEEZE OUT SOME RAIN DROPS. WEDNESDAY AND THURSDAY WILL BE NOTICEABLY COOLER THAN MONDAY AND TUESDAY AS CANADIAN HIGH PRESSURE DRIFTS ACROSS THE GREAT LAKES REGION. MODELS DIVERGE FOR THE END OF THE WEEK WITH LITTLE CHANGES MADE TO THIS PERIOD. HIGH TEMPERATURES WILL BE DEPENDENT ON THE EXTENT OF CLOUD COVER AND RAIN COVERAGE. CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS FOR FRIDAY INTO THE WEEKEND. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 954 PM CDT SUN JUN 22 2014 A SERIES OF SHORT WAVES IN EASTERLY FLOW AND SURFACE FRONT/TROF TO BE FOCUS OF ISOLD TO SCATTERED SHOWERS AND STORMS THIS PERIOD. SOME MVFR FOG WILL DEVELOP TNGT...BUT AS SHRA ACTIVITY IS EXPECTED TO LEAD TO MIXING...SO VSBYS NOT EXPECTED TO DROP AS FAR AS THE PAST FEW NIGHTS EXCEPT NEAR LAKE WHERE FOG OFF LAKE MI WILL AFFECT COASTAL AREAS. SHOWER ACTIVITY TO SHIFT EAST OUT OF AREA MON AFTN AS SFC FRONT/TROF PUSHES EAST. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........TE SYNOPSIS.......SKOWRONSKI SHORT TERM.....SKOWRONSKI LONG TERM......ALLEN AVIATION.......TE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
741 PM CDT SUN JUN 22 2014 .UPDATE... ISSUED AT 740 PM CDT SUN JUN 22 2014 CONCERNING THE FLASH FLOOD WATCH AND HEAVY RAIN POTENTIAL. TRENDS HAVE REALLY BEEN ON THE DECREASE FOR THE INGREDIENTS NEEDED FOR FLASH FLOODING TONIGHT. CURRENTLY A WEAKLY CONVERGENT TROUGH RUNS ABOUT ON I-35 THROUGH IA AND SRN MN THEN ANGLES TO NEAR KAXN IN MN. FURTHER WEST THE STABILIZING FRONT WAS EXTENDING FROM NW OF KFSD-KINL AND PROGRESSING SE WITH MID-50S DEWPOINTS /KABR 00Z RAOB WITH 0.70 INCH PRECIPITABLE WATER/. INDICATIONS ARE FOR A BIT FASTER COLD FRONTAL PUSH OVERNIGHT INTO THE MORNING HOURS WHICH MEANS MONDAY WILL NOT HAVE ANY FLASH FLOOD THREAT. PER THE 22.23Z RAP...THE 925 MB WINDS ARE ALL NW IN THE FORECAST AREA BY 15Z. IN FACT...MOST WINDS ON AND WEST OF THE MISS RIVER VEER AROUND TO NW AT 925 MB BY 08Z. THIS PROVIDES A MORE PROGRESSIVE SOLUTION TO ANY STORM ACTIVITY TONIGHT. CONCERNING THE STORMS EXPECTED TONIGHT...THE INSTABILITY AFTER THE AFTERNOON STORMS HAS SEVERELY IMPACTED THE CAPE AVAILABLE FOR HEAVY RAINFALL TONIGHT. RIGHT NOW THE FORECAST AREA IS IN THE HUNDREDS OF J/KG OF MUCAPE AND RADAR IS SHOWING LITTLE SIGN OF ANY ORGANIZED RAIN THREAT. THE COMPLEX NEAR ALBERT LEA MN HAS NOW DISSIPATED. THERE IS A BIT OF FRONTOGENESIS IN MID LEVELS THAT TRIES TO PRODUCE SOME LIFT FROM BLACK RIVER FALLS WI INTO NERN IA OVER NEXT SEVERAL HOURS. BUT WITH LIMITED OR DIMINISHING CAPES...ANY STORMS THAT FORM WILL STRUGGLE TO PRODUCE HEAVY RAIN. WITH THAT SAID..THE AIR MASS STILL HAS POTENT MOISTURE /KMPX 00Z RAOB 1.36 INCH PRECIPITABLE WATER/. IT IS JUST THAT THE ORGANIZATION AND INSTABILITY ARE NOT THERE FOR HEAVY RAIN. IN FACT...WILL ALSO ASSESS THE RAIN COVERAGE TONIGHT...IT LOOKS MUCH TOO HIGH PER LATEST HRRR RUNS AND 22.21Z HOPWRF RUN FROM MPX. BOTTOM LINE IS WE HAVE STARTED TO MESSAGE A REDUCED FLASH FLOOD THREAT...AND THE FLASH FLOOD WATCH WILL BE CANCELLED BY 9 PM UNLESS SOMETHING CHANGES. HAVE ALREADY REMOVED TAYLOR AND CLARK COUNTIES. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 334 PM CDT SUN JUN 22 2014 THE MAIN FOCUS THROUGH TOMORROW IS ON CONVECTIVE TRENDS AND WHETHER ANY FLASH FLOODING IS STILL POSSIBLE. AN MCV FROM OVERNIGHT HAS COME THROUGH MUCH OF THE REGION FROM LATE THIS MORNING INTO THE EARLY AFTERNOON HOURS AND HAS KICKED UP A BAND OF CONVECTION/RAIN OUT AHEAD OF IT. MUCH OF THE 22.12Z GUIDANCE HAS NOT DONE A VERY GOOD JOB OF PICKING UP ON THIS FEATURE AND STILL WANT TO DEVELOP A WIDE SWATH OF CONVECTION ACROSS THE REGION THIS EVENING. THE HRRR HAS DONE A DECENT JOB OF CAPTURING THIS CONVECTION AND CLEARS MOST OF THE REGION FROM THE WEST EARLY THIS EVENING. THE MOST UNSTABLE AIR MASS APPEARS TO STAY OUT AHEAD OF THE MCV...SO AM NOT EXPECTING MUCH IN THE WAY OF SEVERE DEVELOPMENT BEHIND IT. CONFIDENCE IS NOT VERY HIGH WITH HOW TONIGHT WILL PAN OUT WITH THE MAIN COLD FRONT STILL OFF TO THE WEST...SO WILL KEEP THE FLASH FLOOD WATCH GOING FOR THE TIME BEING AND LET THE EVENING PLAY OUT A BIT MORE BEFORE CANNING IT. THE 22.12Z NAM/GFS/GEM DID TREND FASTER WITH PUSHING THE PRECIPITATION/MID LEVEL TROUGH/SFC LOW OFF TO THE EAST TOMORROW MORNING...SO HAVE TRENDED A BIT FASTER WITH ENDING THE RAIN CHANCES TOMORROW. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 334 PM CDT SUN JUN 22 2014 A BRIEF DRY PERIOD IS EXPECTED MONDAY NIGHT INTO TUESDAY MORNING AS SUBSIDENT AIR COMES IN THE WAKE OF THE TROUGH. ANOTHER COLD FRONT WILL DROP DOWN FROM CANADA TUESDAY AFTERNOON AND BRING THE NEXT CHANCE OF RAIN ALONG WITH IT. SKINNY CAPE PROFILE WITH THIS FEATURE WITH LESS THAN 1000 J/KG OF MLCAPE EXPECTED...SO NOT THINKING THAT THIS WILL BE A SEVERE WEATHER PRODUCER AT THIS POINT. AFTER THAT FRONT DROPS TO THE SOUTH IT APPEARS TO STALL OUT FROM THE HIGH PLAINS ON DOWN SOUTHEAST THROUGH THE MID MISSISSIPPI RIVER VALLEY. CONFIDENCE NOT VERY HIGH WITH OUR PRECIPITATION CHANCES TOWARD THE END OF THE WEEK...BUT ALSO DID NOT HAVE MUCH OF A CHANCE TO DIG INTO THE DETAILS WITH CONVECTION ON GOING...SO HAVE GONE WITH THE CONSENSUS OF THE MODEL BLENDS FOR NOW. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 641 PM CDT SUN JUN 22 2014 MESSY AVIATION FORECAST NEXT 6 TO 12 HOURS AS WEAKLY UNSTABLE AND MOIST AIR MASS REMAINS IN PLACE ACROSS SOUTHEAST MINNESOTA AND WESTERN WISCONSIN. PULSE...LOOSELY ORGANIZED SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED ALONG I-35 AND NEAR KRST. UNTIL A COOL FRONT PASSES THROUGH OVERNIGHT...CAN NOT RULE OUT SHOWERS AND ISOLATED TSTORMS BUT EXPECTING LOW COVERAGE AND INTENSITY. WOULD THINK SOME OF THE ACTIVITY IS DIURNAL...AND WITH BEST MOISTURE TRANSPORT MOVING OFF TO THE EAST...THERE SHOULD NOT BE A HUGE UPTICK IN CONVECTIVE ACTIVITY. THUS...AVIATION IMPACTS DUE TO STORMS ARE LOW...HOWEVER WILL MAINTAIN A VCSH/VCTS GROUP THROUGH EARLY OVERNIGHT UNTIL FRONT CLEAR THINGS OUT. PLAN ON VFR CONDITIONS MONDAY WITH NORTHWEST WINDS USHERING IN A DRIER AIR MASS...WITH SCATTERED CU DEVELOPING WITH BASES BETWEEN 5 AND 6 KFT. && .HYDROLOGY... ISSUED AT 334 PM CDT SUN JUN 22 2014 HEAVY RAINFALL FROM LAST WEEK HAS PRIMED THE GROUND FOR ADDITIONAL FLOODING WITH ANY STORMS THAT MAY MOVE THROUGH. THE STORMS TODAY HAD SOME BRIEFLY INTENSE RAINFALL RATES AT ABOUT 2 INCHES PER HOUR THOUGH THEY ONLY LASTED FOR ABOUT A HALF HOUR. MANY AREA RIVERS ARE STILL ELEVATED FROM THE RECENT RAINFALL AND WILL LIKELY STAY THAT WAY THROUGH THE WEEK. CONFIDENCE IS NOT VERY HIGH AT THIS POINT ABOUT WHETHER THE FLASH FLOOD WATCH IS STILL NECESSARY FOR TONIGHT...BUT WANT TO MAKE SURE THAT CONDITIONS WILL BE OKAY BEFORE DROPPING IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR WIZ032>034-041- 042-053>055-061. MN...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR IAZ008>011-018- 019-029-030. && $$ UPDATE...BAUMGARDT SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...ZT HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
641 PM CDT SUN JUN 22 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 334 PM CDT SUN JUN 22 2014 THE MAIN FOCUS THROUGH TOMORROW IS ON CONVECTIVE TRENDS AND WHETHER ANY FLASH FLOODING IS STILL POSSIBLE. AN MCV FROM OVERNIGHT HAS COME THROUGH MUCH OF THE REGION FROM LATE THIS MORNING INTO THE EARLY AFTERNOON HOURS AND HAS KICKED UP A BAND OF CONVECTION/RAIN OUT AHEAD OF IT. MUCH OF THE 22.12Z GUIDANCE HAS NOT DONE A VERY GOOD JOB OF PICKING UP ON THIS FEATURE AND STILL WANT TO DEVELOP A WIDE SWATH OF CONVECTION ACROSS THE REGION THIS EVENING. THE HRRR HAS DONE A DECENT JOB OF CAPTURING THIS CONVECTION AND CLEARS MOST OF THE REGION FROM THE WEST EARLY THIS EVENING. THE MOST UNSTABLE AIR MASS APPEARS TO STAY OUT AHEAD OF THE MCV...SO AM NOT EXPECTING MUCH IN THE WAY OF SEVERE DEVELOPMENT BEHIND IT. CONFIDENCE IS NOT VERY HIGH WITH HOW TONIGHT WILL PAN OUT WITH THE MAIN COLD FRONT STILL OFF TO THE WEST...SO WILL KEEP THE FLASH FLOOD WATCH GOING FOR THE TIME BEING AND LET THE EVENING PLAY OUT A BIT MORE BEFORE CANNING IT. THE 22.12Z NAM/GFS/GEM DID TREND FASTER WITH PUSHING THE PRECIPITATION/MID LEVEL TROUGH/SFC LOW OFF TO THE EAST TOMORROW MORNING...SO HAVE TRENDED A BIT FASTER WITH ENDING THE RAIN CHANCES TOMORROW. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 334 PM CDT SUN JUN 22 2014 A BRIEF DRY PERIOD IS EXPECTED MONDAY NIGHT INTO TUESDAY MORNING AS SUBSIDENT AIR COMES IN THE WAKE OF THE TROUGH. ANOTHER COLD FRONT WILL DROP DOWN FROM CANADA TUESDAY AFTERNOON AND BRING THE NEXT CHANCE OF RAIN ALONG WITH IT. SKINNY CAPE PROFILE WITH THIS FEATURE WITH LESS THAN 1000 J/KG OF MLCAPE EXPECTED...SO NOT THINKING THAT THIS WILL BE A SEVERE WEATHER PRODUCER AT THIS POINT. AFTER THAT FRONT DROPS TO THE SOUTH IT APPEARS TO STALL OUT FROM THE HIGH PLAINS ON DOWN SOUTHEAST THROUGH THE MID MISSISSIPPI RIVER VALLEY. CONFIDENCE NOT VERY HIGH WITH OUR PRECIPITATION CHANCES TOWARD THE END OF THE WEEK...BUT ALSO DID NOT HAVE MUCH OF A CHANCE TO DIG INTO THE DETAILS WITH CONVECTION ON GOING...SO HAVE GONE WITH THE CONSENSUS OF THE MODEL BLENDS FOR NOW. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 641 PM CDT SUN JUN 22 2014 MESSY AVIATION FORECAST NEXT 6 TO 12 HOURS AS WEAKLY UNSTABLE AND MOIST AIR MASS REMAINS IN PLACE ACROSS SOUTHEAST MINNESOTA AND WESTERN WISCONSIN. PULSE...LOOSELY ORGANIZED SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED ALONG I-35 AND NEAR KRST. UNTIL A COOL FRONT PASSES THROUGH OVERNIGHT...CAN NOT RULE OUT SHOWERS AND ISOLATED TSTORMS BUT EXPECTING LOW COVERAGE AND INTENSITY. WOULD THINK SOME OF THE ACTIVITY IS DIURNAL...AND WITH BEST MOISTURE TRANSPORT MOVING OFF TO THE EAST...THERE SHOULD NOT BE A HUGE UPTICK IN CONVECTIVE ACTIVITY. THUS...AVIATION IMPACTS DUE TO STORMS ARE LOW...HOWEVER WILL MAINTAIN A VCSH/VCTS GROUP THROUGH EARLY OVERNIGHT UNTIL FRONT CLEAR THINGS OUT. PLAN ON VFR CONDITIONS MONDAY WITH NORTHWEST WINDS USHERING IN A DRIER AIR MASS...WITH SCATTERED CU DEVELOPING WITH BASES BETWEEN 5 AND 6 KFT. && .HYDROLOGY... ISSUED AT 334 PM CDT SUN JUN 22 2014 HEAVY RAINFALL FROM LAST WEEK HAS PRIMED THE GROUND FOR ADDITIONAL FLOODING WITH ANY STORMS THAT MAY MOVE THROUGH. THE STORMS TODAY HAD SOME BRIEFLY INTENSE RAINFALL RATES AT ABOUT 2 INCHES PER HOUR THOUGH THEY ONLY LASTED FOR ABOUT A HALF HOUR. MANY AREA RIVERS ARE STILL ELEVATED FROM THE RECENT RAINFALL AND WILL LIKELY STAY THAT WAY THROUGH THE WEEK. CONFIDENCE IS NOT VERY HIGH AT THIS POINT ABOUT WHETHER THE FLASH FLOOD WATCH IS STILL NECESSARY FOR TONIGHT...BUT WANT TO MAKE SURE THAT CONDITIONS WILL BE OKAY BEFORE DROPPING IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR WIZ017-029- 032>034-041-042-053>055-061. MN...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR IAZ008>011-018- 019-029-030. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...ZT HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
347 PM CDT SAT JUN 21 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 345 PM CDT SAT JUN 21 2014 AT 3 PM...A MESOSCALE CONVECTIVE VORTICITY...GENERATED FROM THE THUNDERSTORMS IN NEBRASKA AND SOUTH DAKOTA LAST EVENING...WAS MOVING EAST THROUGH SOUTHERN WISCONSIN. THIS SYSTEM IS GENERATING SHOWERS AND A FEW THUNDERSTORMS IN AN AREA OF 2500 J/KG SURFACE CAPES. BOTH THE 21.12Z ARW AND LATEST HRRR ARE IN GOOD AGREEMENT THAT A FEW SHOWERS WILL LINGER ACROSS ADAMS AND JUNEAU COUNTIES IN CENTRAL WISCONSIN THROUGH 22.03Z...AND THEN THE REMAINDER OF TONIGHT WILL BE DRY AS SUBSIDENCE BUILDS ACROSS THE AREA IN THE WAKE OF THE CONVECTIVELY INDUCED VORT MAX AND SHORT WAVE RIDGE. ON SUNDAY...THE 21.12Z MODELS ARE IN GOOD AGREEMENT THAT SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP DURING THE MORNING ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA AHEAD OF AN APPROACHING COLD FRONT AND SHORT WAVE TROUGH MOVING OUT OF THE CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS THEN BECOME MORE WIDESPREAD ACROSS THE ENTIRE FORECAST AREA AS THE UPPER LEVEL DIVERGENCE INCREASES... THE AREA ENTERS THE RIGHT ENTRANCE REGION OF A 50 KNOT 250 MB JET...AND THE SURFACE BASE CAPES CLIMB INTO THE 3-4K J/KG RANGE. WHILE THE MODELS ARE IN AGREEMENT WITH THIS...THEY DO DIFFER SOME ON HOW ORGANIZED THIS CONVECTION BECOMES DURING THE AFTERNOON. THE ARW SUGGEST A LINE OF STORMS BY EARLY AFTERNOON. MEANWHILE THE 21.12Z SPC WRF SUGGESTS THAT THE CONVECTION WILL BE LESS ORGANIZED. WHILE THE 0-3 KM AND 0-6 KM SHEAR IS NOT SUFFICIENT FOR THE DEVELOPMENT OF SUPERCELLS...THE MID LEVEL LAPSE RATES ARE RUNNING IN THE 7 TO 8 C/KM RANGE WHICH WOULD BE SUFFICIENT FOR THE DEVELOPMENT OF LARGE HAIL AND DRY AIR BELOW THE CLOUDS MAY AID IN STRENGTHENING THE DOWN DRAFTS...SO WILL HAVE TO WATCH OUT FOR PULSE SEVERE STORMS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 345 PM CDT SAT JUN 21 2014 FROM SUNDAY NIGHT INTO MONDAY...THE CONVECTION BECOMES MORE ORGANIZED AS THE COLD FRONT AND SURFACE LOW MOVES SLOWLY THROUGH THE FORECAST AREA. STRONG 850 MB MOISTURE JET WILL RESULT IN THE DEVELOPMENT OF A MESOSCALE CONVECTIVE COMPLEX. IN ADDITION... PRECIPITABLE WATER VALUES CLIMB INTO THE 1.7 TO 1.9 INCH RANGE AND WARM CLOUD DEPTHS CLIMB TO 4 KM AHEAD OF THE SURFACE LOW. THIS WILL RESULT IN THE THREAT OF HEAVY RAIN AND POTENTIALLY SOME MORE FLOODING. WITH MODELS DEVIATING ON THE TIMING...LOCATION OF THE SURFACE LOW...AND STRENGTH OF THE SHORT WAVE TROUGH...HELD OFF ISSUING A FLOOD WATCH FOR NOW. WHILE THE 0-6 KM SHEAR REMAINS WEAK...THE 0-3 KM DOES EXCEED 30 KNOTS AND THIS COULD RESULT IN SOME WIND DAMAGE AS THE SYSTEM EVOLVES. MONDAY NIGHT IS NOW LOOKING DRY IN ALL OF THE DETERMINISTIC MODELS AS SUBSIDENCE DEVELOPS IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM. AS A RESULT...EITHER REDUCED OR TOOK OUT THE PRECIPITATION CHANCES ACROSS THE ENTIRE FORECAST AREA. FROM TUESDAY THROUGH THURSDAY....A CANADIAN COLD FRONT DROPS INTO THE REGION. WHILE THE MODELS HAVE BEEN CONSISTENT AT DOING THIS... THEY CONTINUE TO STRUGGLE ON HOW FAR SOUTH THIS FRONT WILL GET. THE MODELS ALSO CONTINUE TO SHOW THAT SEVERAL SHORT WAVE TROUGHS WILL MOVE ALONG THIS BOUNDARY. HOWEVER THERE IS ONLY WEAK MOISTURE TRANSPORT INTO THE REGION WHICH RESULTS IN WEAK 0-3 KM AND 0-6 KM SHEAR...THUS NOT EXPECTING ANY SEVERE WEATHER AT THIS TIME. FROM THURSDAY NIGHT INTO SATURDAY...A PATTERN SHIFT OCCURS AS A LONG WAVE TROUGH MOVES INTO THE WESTERN UNITED STATES. WHILE BOTH THE GFS AND ECMWF ARE IN AGREEMENT THAT AND UPPER LEVEL RIDGE WILL BUILD AHEAD OF THIS TROUGH...THERE CONTINUES TO BE QUESTIONS ON HOW FAR WEST THIS RIDGE WILL END UP AND THIS WILL GREATLY AFFECT WHETHER WE WILL SEE PRECIPITATION OR NOT. DUE TO THIS...JUTS STAYED WITH THE MODEL CONSENSUS FOR NOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1236 PM CDT SAT JUN 21 2014 A BAND OF LIGHT RAIN SHOWERS AND UPPER LEVEL CLOUD COVER WILL SHIFT TO THE EAST QUICKLY THIS AFTERNOON WITH THE REMNANTS OF AN OVERNIGHT STORM SYSTEM MOVING INTO CENTRAL WISCONSIN. SKIES WILL CLEAR OUT WITH WINDS REMAINING LIGHT THROUGH TOMORROW MORNING AS A WEAK RIDGE OF HIGH PRESSURE MOVES IN. WINDS WILL SHIFT AROUND TO THE SOUTHEAST TOMORROW MORNING AHEAD OF THE NEXT SYSTEM WHICH MAY BRING SOME THUNDERSTORMS IN ON SUNDAY AFTERNOON/EVENING. && .HYDROLOGY... ISSUED AT 345 PM CDT SAT JUN 21 2014 THE MISSISSIPPI TRIBUTARIES HAVE CRESTED AND ARE NOW FALLING. MEANWHILE THE MISSISSIPPI RIVER IS RISING WITH FLOODING EXPECTED AT WABASHA...WINONA...AND MCGREGOR. AT THIS TIME...LA CROSSE IS NOT EXPECTED TO REACH FLOOD STAGE. HOWEVER THIS COULD CHANGE DEPENDING ON HOW MUCH RAIN FALLS ON SUNDAY NIGHT. BETWEEN 1 AND 3 INCHES OF RAIN LOOKS POSSIBLE ON SUNDAY NIGHT...BUT DUE TO MODEL INCONSISTENCIES HELD OFF ISSUING A FLOOD WATCH FOR NOW. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...HALBACH HYDROLOGY...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1236 PM CDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1137 AM CDT SAT JUN 21 2014 REMNANT MCV FROM LAST NIGHTS CONVECTION FURTHER SOUTHWEST IS CURRENTLY TRACKING EAST ACROSS NORTHEAST IOWA/SOUTHWEST WISCONSIN. THIS HAS LEAD TO MUCH MORE CLOUD COVER AND SOME LIGHT RAIN SHOWERS ALONG THE MISSISSIPPI RIVER. 16Z RAP ANALYSIS SHOWS THE BETTER SB/MLCAPE CHANNEL RUNNING OUT AHEAD OF THIS MCV INTO SOUTHWEST/WEST CENTRAL WISCONSIN WITH IT BULLSEYED ON THE DELLS. THE MAIN CONVECTIVE CHANCES WILL BE OVER THE NEXT FEW HOURS BEFORE THIS FEATURE MOVES OFF TO THE EAST BY MID AFTERNOON. ONCE IT DOES MOVE OFF TO THE EAST...IT APPEARS THAT WE WILL SEE A DRY PERIOD GOING THROUGH TONIGHT AS A RIDGE OF HIGH PRESSURE MOVES IN WITH DRIER/STABLE AIR. THUS...HAVE ADJUSTED TRENDS TO BE CLOUDIER/RAINIER THIS MORNING/EARLY AFTERNOON AND THEN DROPPED CHANCES FOR PRECIPITATION FOR LATE THIS AFTERNOON/EARLY EVENING. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 316 AM CDT SAT JUN 21 2014 MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD. REGIONAL RADARS SHOWING A CONVECTIVE COMPLEX THIS MORNING OVER SOUTHWEST IOWA INTO SOUTHERN NEBRASKA. MOVEMENT OF THE ACTIVITY IS SLOWLY TO THE SOUTH/SOUTHEAST AND EXPECT THAT THIS WILL NOT IMPACT THE FORECAST AREA THIS MORNING. OTHER SHOWERS HAVE DEVELOPED THIS MORNING OVER NORTH CENTRAL WISCONSIN ALONG THE LEADING EDGE OF A WEAK BOUNDARY THAT HAS PUSHED IN FROM THE EAST. AS THE FLOW AHEAD OF THIS BOUNDARY BECOMES MORE SOUTH TO SOUTHWEST...ANTICIPATE THAT IT WILL START TO RETREAT WITH ANY SHOWERS ALONG MOVING OUT OF THE AREA BY MID MORNING. AFTER THAT...A FAIR AMOUNT OF UNCERTAINTY ON HOW THE REST OF THE DAY WILL PLAY OUT. THE 21.00Z NAM SUGGESTS A WEAK SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA THIS AFTERNOON AND EVENING WHILE THE 21.00Z GFS REALLY DOES NOT SHOW THIS FEATURE. LOOKING AT THE WATER VAPOR IMAGERY...IT DOES SUGGEST THERE COULD BE A WEAK WAVE COMING ACROSS THE DAKOTAS SIMILAR TO WHAT THE NAM INDICATES. WHETHER THIS WAVE WILL PRODUCE ANY CONVECTION IS QUESTIONABLE AS WELL. THE NAM ONLY SHOWS SOME WEAK PV ADVECTION IN THE 500-300 MB LAYER WITH LITTLE OR NO MOISTURE TRANSPORT INTO THE REGION. DESPITE THIS...IT DEVELOPS SOME CONVECTION ACROSS IOWA WHICH IS SIMILAR TO WHAT THE 21.00Z ECMWF SHOWS. THE GFS...DESPITE NOT HAVING THE WAVE...BLOWS UP EVEN MORE CONVECTION OVER MUCH OF THE AREA. THE 21.00Z HI-RES ARW SUGGESTS THAT ANY CONVECTION SHOULD DEVELOP SOUTHEAST OF THE AREA IN CONJUNCTION WITH THE MCV THAT MOVES OUT OF THE ONGOING IOWA CONVECTION. WILL JUST CARRY SOME 20 TO 30 PERCENT AFTERNOON RAIN CHANCES WITH THE HIGHER CHANCES ACROSS THE SOUTH AND EAST SECTIONS TO FAVOR THE NAM AND ARW SOLUTIONS. FAIRLY GOOD AGREEMENT THAT A STRONGER SHORT WAVE TROUGH WILL CROSS THE ROCKIES IN THE ZONAL FLOW AND MOVE ACROSS THE UPPER MIDWEST LATE TONIGHT THROUGH SUNDAY. SOME DIFFERENCES WITH THE TIMING OF THIS WAVE WITH THE NAM FASTER TO BRING IT IN THAN THE GFS OR ECMWF. THIS WAVE SHOULD BE ABLE TO PRODUCE SOME WEAK TO MODERATE PV ADVECTION IN THE 500-300 MB LAYER WITH 3 TO 6 UBAR/S OF UP GLIDE ON THE 305K ISENTROPIC SURFACE. EXPECT THAT THE AREA WILL BE CAUGHT IN BETWEEN SYSTEMS THIS EVENING WITH THE POSSIBILITY OF SOME DYING ACTIVITY FROM ANYTHING THAT DEVELOPS TODAY AND AN INCREASE OVERNIGHT AHEAD OF THE APPROACHING WAVE...ESPECIALLY ACROSS THE WEST. THE FORCING FROM THIS WAVE WILL CONTINUE TO SLOWLY INCREASE SUNDAY AS IT PUSHES A WEAK SURFACE BOUNDARY TOWARD THE AREA AS WELL. WILL SHOW THE RAIN CHANCES INCREASING TO ABOUT 40 PERCENT LATE TONIGHT ACROSS THE WEST AND UP TO 50 PERCENT FOR MUCH OF THE AREA SUNDAY. AS THIS SHORT WAVE TROUGH MOVES PAST THE AREA...THE GENERAL CONSENSUS AMONG THE MODELS IS THAT IT WILL BE QUICKLY FOLLOWED BY ANOTHER ONE FOR SUNDAY NIGHT AND MONDAY. THIS SHOULD PRODUCE ANOTHER ROUND OF WEAK PV ADVECTION...2-6 UBAR/S OF UP GLIDE ON THE 305K ISENTROPIC SURFACE ALONG WITH SOME WEAK FRONTOGENESIS IN THE 850-500 MB LAYER. THE WEAK SURFACE BOUNDARY THAT GETS PUSHED INTO THE AREA SUNDAY WILL STILL BE OVER THE REGION WITH THE NAM AND ECMWF SHOWING A WEAK SURFACE LOW MOVING ALONG THE BOUNDARY. THIS SHOULD BE ENOUGH TO PRODUCE A FAIR AMOUNT OF CONVECTION AND WILL CONTINUE WITH 40 TO 50 PERCENT RAIN CHANCES SUNDAY NIGHT INCREASING TO 60 PERCENT ACROSS THE SOUTHEAST FOR MONDAY. THE RISK FOR ORGANIZED SEVERE WEATHER LOOKS PRETTY LOW THROUGH MONDAY. WHILE DECENT CAPE SHOULD BE AVAILABLE EACH DAY...1000-2000 J/KG OF ML CAPE...THE WIND SHEAR LOOKS MARGINAL. THE 0-3KM SHEAR LOOKS TO BE 20 TO 30 KNOTS EACH DAY WHICH COULD SUPPORT SOME STRONG STORMS WITH A LITTLE BIT OF WIND POTENTIAL. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 316 AM CDT SAT JUN 21 2014 THE UNSETTLED PATTERN LOOKS TO CONTINUE THROUGH MUCH OF THE WEEK. AT SOME POINT...THE REMAINS OF THE UPPER LEVEL LOW CURRENTLY OVER MANITOBA WILL BECOME AN OPEN WAVE AND TRACK ACROSS THE UPPER MIDWEST. WITH THE WEAK ZONAL FLOW...THIS DOES NOT LOOK TO BE A QUICK PROCESS AND COULD TAKE MOST OF THE WEEK BEFORE IT FINALLY MOVES PAST THE REGION. THIS WILL CONTINUE TO PROVIDE A CHANCE OF RAIN TO THE AREA THROUGH THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1236 PM CDT SAT JUN 21 2014 A BAND OF LIGHT RAIN SHOWERS AND UPPER LEVEL CLOUD COVER WILL SHIFT TO THE EAST QUICKLY THIS AFTERNOON WITH THE REMNANTS OF AN OVERNIGHT STORM SYSTEM MOVING INTO CENTRAL WISCONSIN. SKIES WILL CLEAR OUT WITH WINDS REMAINING LIGHT THROUGH TOMORROW MORNING AS A WEAK RIDGE OF HIGH PRESSURE MOVES IN. WINDS WILL SHIFT AROUND TO THE SOUTHEAST TOMORROW MORNING AHEAD OF THE NEXT SYSTEM WHICH MAY BRING SOME THUNDERSTORMS IN ON SUNDAY AFTERNOON/EVENING. && .HYDROLOGY... ISSUED AT 316 AM CDT SAT JUN 21 2014 MANY OF THE RIVERS ACROSS THE AREA REMAIN HIGH OR ARE FLOODING FROM ALL THE RECENT RAINS. LATEST INDICATIONS ARE THAT OUTSIDE OF THE MISSISSIPPI RIVER...A LOT OF THE RIVERS ARE CRESTING OR VERY CLOSE TO CRESTING AND SHOULD START TO GO DOWN HEADING THROUGH THE WEEKEND. CRESTS ON THE MISSISSIPPI RIVER ARE NOT EXPECTED TO START OCCURRING UNTIL ABOUT THE MIDDLE OF THE WEEK. SEE THE LATEST FLOOD STATEMENTS FOR SPECIFIC FORECAST INFORMATION. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...04 LONG TERM...04 AVIATION...HALBACH HYDROLOGY...04
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1213 PM CDT SAT JUN 21 2014 .UPDATE...REMNANT MESOSCALE CONVECTIVE VORTEX SHIFTING TOWARD THE AREA FROM THE WEST. THIS FEATURE IS EXPECTED TO SHIFT THROUGH THE AREA THIS AFTERNOON. AREA OF SHOWERS SEEN WITH THIS FEATURE. MORE ISOLATED SHOWERS AND STORMS WERE OBSERVED EAST OF THIS FEATURE AS WELL. MESOSCALE MODELS TRYING TO SHOW SCATTERED SHOWERS AND STORMS DEVELOPING BY EARLY THIS AFTERNOON ACROSS PORTIONS OF THE AREA...THEN SHIFTING EAST SOUTHEAST THROUGH THE AREA BY 22Z. 0 TO 6 KM SHEAR IS WEAK BUT EFFECTIVE LAYER SHEAR IS BETTER. SPC HAS PARTS OF THE SOUTHWEST COUNTIES IN SLIGHT RISK SEVERE THIS AFTERNOON. A FEW STRONG TO SEVERE STORMS ARE POSSIBLE HERE GIVEN EXPECTED MEAN LAYER CAPES AND EFFECTIVE SHEAR PROFILES. AREA FORECAST SOUNDINGS FROM RAP/NAM/GFS SHOWING MEAN LAYER CAPE OF 1500 TO 2000 J/KG DEVELOPING IN THE WESTERN PORTIONS OF THE AREA. LOW CLOUDS WOULD HAVE TO CLEAR THE EASTERN PORTIONS OF THE AREA TO GET THAT UNSTABLE. MODELS ARE TRYING TO MIX OUT THIS LOW DECK...BUT CURRENT TRENDS SUGGEST THAT IT WILL LINGER FOR A GOOD PART OF THE AFTERNOON...IF NOT ALL OF IT. THIS WOULD ALSO REINFORCE SURFACE BOUNDARY RUNNING NORTHWEST TO SOUTHEAST ACROSS SOUTH CENTRAL WISCONSIN...WHICH MAY AID WITH LOW LEVEL CONVERGENCE. FOR NOW...WILL CONTINUE TO BRING IN CHANCE/SCATTERED POPS THIS AFTERNOON...ESPECIALLY IN THE SOUTHERN PORTIONS OF THE AREA. TEMPERATURES JUMPED INTO THE UPPER 70S TO LOWER 80S IN THE WEST WHERE THERE WAS SOME SUNSHINE...AND SHOULD RISE INTO THE LOWER TO MID 80S. THE EAST REMAINS IN THE 60S WITH THE LOW STRATUS. MAY LOWER HIGHS IN THE EAST WITH CLOUDS LIKELY TO REMAIN. && .AVIATION/18Z TAFS/...MADISON SHOULD SEE CEILINGS RISE ABOVE MVFR LEVELS BY EARLY THIS AFTERNOON. BETTER CHANCES FOR SHOWERS AND STORMS ARE HERE...WILL MENTION VICINITY THUNDER FOR NOW IN TAFS UNTIL 22Z. MVFR VISIBILITIES ARE POSSIBLE IN ANY STORMS. THE EASTERN SITES SHOULD SEE CEILINGS RISE ABOVE ALTERNATE MINIMUMS EARLY THIS AFTERNOON...THEN REMAIN IN THE MVFR/IFR AREA THROUGH THE REST OF THE AFTERNOON INTO THIS EVENING. MAY SEE SOME PEAKS OF SUN...BUT CURRENT TRENDS SUGGEST THIS LOW STRATUS DECK WILL LINGER. ALSO WILL MENTION VICINITY THUNDER UNTIL 22Z. LOW STRATUS AND FOG...POSSIBLY DENSE FOG...WILL RETURN TO THE EASTERN SITES BY 03Z SUNDAY...AND LINGER INTO AT LEAST 15Z SUNDAY. EXPECT VISIBILITIES DOWN TO 1/4 TO 1/2 MILE HERE AFTER 06Z SUNDAY...WITH CEILINGS DOWN TO 100 TO 200 FEET ABOVE GROUND LEVEL. THESE CONDITIONS WILL APPROACH OR REACH AIRPORT MINIMUMS. MADISON MAY SEE LOW STRATUS MOVE BACK IN AS WELL AFTER 06Z SUNDAY...LINGERING TO AROUND 15Z SUNDAY. CEILINGS NEAR ALTERNATE MINIMUMS WITH VISIBILITIES DOWN TO 1/2 MILE ARE POSSIBLE. 1/4 MILE VISIBILITIES NOT OUT OF THE QUESTION HERE EITHER...NEAR AIRPORT MINIMUMS. SHOULD SEE CONDITIONS SLOWLY IMPROVE IN THE LATE MORNING AND AFTERNOON TO MVFR OR BETTER. && .MARINE...EXTENDED THE MARINE DENSE FOG ADVISORY UNTIL 15Z SUNDAY. AREA WEB CAMERAS STILL SHOWING DENSE FOG OVER THE WATER...WITH WARM MOIST AIR MASS OVER COLD LAKE WATERS. THIS SHOULD PERSIST INTO AT LEAST MID MORNING ON SUNDAY...PERHAPS LONGER. MAY NEED TO EXTEND FURTHER OUT TOMORROW MORNING IF CONDITIONS DO NOT IMPROVE. && .PREV DISCUSSION... /ISSUED 339 AM CDT SAT JUN 21 2014/ SHORT TERM... TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM. WE HAVE A RATHER COMPLICATED FORECAST FOR TODAY AND TONIGHT. FOR STARTERS...A LARGE AREA OF LOW STRATUS/FOG AND COOL AIR HAS OVERSPREAD THE AREA FROM AN EASTERLY FLOW OFF LAKE MICHIGAN. THE EXACT DISSIPATION OF THIS DECK IS ALWAYS TRICKY AND WILL LIKELY IMPACT THE AIRSHOW SCHEDULED FOR THE LAKE SHORE OF MILWAUKEE TODAY. A DENSE FOG ADVISORY IS IN EFFECT FOR THE LAKE SHORE COUNTIES THROUGH 9 AM. IN GENERAL...VISIBILITIES ARE BETTER THAN 1/2 MILE...BUT AREA WEB CAMS SHOW SOME SPOTTY DENSE FOG...ESPECIALLY RIGHT ALONG THE LAKE. SO IT/S PRUDENT TO KEEP THIS GOING THROUGH MID MORNING. THE WESTERN EDGE OF THE STRATUS DECK...WEST OF MADISON EARLY THIS MORNING...IS DEFINING A STATIONARY FRONTAL BOUNDARY THAT EXTENDS UP TO A SURFACE LOW OVER EASTERN MINNESOTA. MEANWHILE...MANY OF THE MODELS ARE FIRING OFF SOME ELEVATED CONVECTION THAT PUSHES ACROSS THE CWA THIS MORNING. THIS IS IN ASSOCIATION WITH AN H7 TROF AND RIGHT ENTRANCE REGION OF A DEPARTING UPPER JET. AT THIS WRITING...THAT CONVECTION HASN/T STARTED YET AND CONFIDENCE ISN/T HIGH THAT IT WILL. SO SMALL POPS WILL COVER THAT FOR NOW AND WILL ADJUST IF IT STARTS TO SHOW ITS HAND...OR NOT. NOTHING WILL BE SURFACE BASED DUE TO THE RATHER DEEP CAPPING FROM THE COOLER FLOW OFF THE LAKE. FOR THIS AFTERNOON...THE MODEL SOUNDINGS SUGGEST THE STRATUS AND IT/S SUPPORTIVE LOW LEVEL INVERSION WILL MIX OUT BY AROUND NOON. THE SOUNDINGS SHOW UNCAPPED CAPE OF ABOUT 1500J/KG AVAILABLE THIS AFTERNOON AND WITH THE WEAK FRONTAL BOUNDARY STILL LINGERING...WE COULD SEE A FEW THUNDERSTORMS DEVELOP. DEEP LAYER BULK SHEAR IS ON THE WEAK SIDE...GENERALLY LESS THAN 30KTS...WITH PARAMETERS LOOKING BETTER TO THE SOUTH. IF WE GET DECENT DIFFERENTIAL HEATING ALONG THE EDGE OF THE STATUS...WE COULD SEE A STRONGER SURFACE BOUNDARY AND LLV CONVERGENCE. SPC HAS CLIPPED OUR FAR SOUTH WITH A SLIGHT RISK FOR SVR STORMS. ALTHOUGH IT APPEARS THE BEST CHANCE FOR THE STRONGEST STORMS WILL BE TO OUR SOUTH...THE HIRES ARW AND NMM MODELS BOTH SHOW SOMETHING ROLLING EAST ALONG THE STATE LINE. LOTS OF UNCERTAINTY WITH OVERALL WEAK FORCING WITHIN A MODERATELY UNSTABLE AIRMASS. THE COLDER LOW LEVEL STRATUS JUST COMPLICATES THINGS. SO WILL KEEP POPS ON THE LOWER SIDE WHICH MATCHES THE CONSENSUS OF THE MODELS AND THINKING OF SURROUNDING OFFICES. A BACKDOOR COLD FRONT IS EXPECTED TO DROP THROUGH THE AREA THIS EVENING IN THE WAKE OF A LOW PRESSURE SYSTEM SCOOTING EAST. THIS SHOULD SET THE STAGE FOR MORE FOG AND POSSIBLE LOW CLOUDS. AVIATION/12Z TAFS/... A VERY DIFFICULT FORECAST INDEED. THE COOL EASTERLY FLOW OFF THE LAKE HAS COMBINED WITH THE MOIST AIRMASS IN PLACE THE LAST FEW DAYS...RESULTING IN A HUGE LOWER STRATUS DECK THAT COVERS MUCH OF ERN WISCONSIN AND NRN IL. IT/S CONSISTENTLY 200-300 AGL ACROSS THE AREA. THE LATEST AMDAR AIRCRAFT AND RAP SOUNDING SHOW THIS TO BE ABOUT 2-2.5KFT THICK. THE RAP MIXES IT OUT IN THE MILWAUKEE AREA BY AROUND 17-18Z THIS AFTERNOON...SO IT SHOULD HANG IN TIGHT THROUGH THE MORNING. THE EROSION AT KMSN IS AROUND 15Z. ONCE IT STARTS TO OPEN UP...IT WILL LIKELY LIFT INTO TO STRATOCU DECK BEFORE SCATTERING OUT. THE FOG/LOWER VSBYS SHOULD IMPROVE AFTER SUNRISE...AS WE START TO HEAT THINGS UP AND PUT A LITTLE DISTANCE BETWEEN THE TEMP AND DEWPOINT. THEN WE HAVE THE CHANCE FOR SHOWERS AND THUNDERSTORMS. THE BEST CHANCE FOR ANY STORMS LOOKS TO BE FROM ABOUT 20Z-01Z...OR TRADITIONAL PEAK HEATING. THERE WILL BE A WEAK FRONTAL BOUNDARY IN THE AREA THAT MAY ACT AS A FOCUS FOR THUNDERSTORM DEVELOPMENT. WE WILL BE IN A WEAK FLOW...MODERATELY UNSTABLE ENVIRONMENT THIS AFTERNOON...SO THERE IS PLENTY OF UNCERTAINTY. MORE FOG IS EXPECTED TONIGHT AS A BACKDOOR COLD FRONT SWEEPS DOWN THE LAKE AS WEAK LOW PRESSURE SCOOTS EAST. OF COURSE THIS MEANS MORE FOG AND POSSIBLY LOWER STRATUS AGAIN TONIGHT. LONG TERM... SUNDAY THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE MEDIUM. THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE DAY SUNDAY WITH WEAK 850MB FRONTOGENESIS AND 700 MB UPWARD MOTION. FORECAST SOUNDINGS FOR MADISON SHOW BUILDING CAPE THROUGH THE AFTERNOON WITH NO CAP. HOWEVER...LOW POPS BECAUSE WE MIGHT LACK A TRIGGER FOR ANY THUNDERSTORMS TO DEVELOP DUE TO MID LEVEL RIDGING OVERHEAD. IF THUNDERSTORMS DEVELOP...THE SHEAR IS WEAK SO NOT LOOKING FOR SEVERE STORMS DURING THE DAY. NEAR THE LAKE...WINDS WILL CONTINUE TO BE LIGHT AND EASTERLY ON SUNDAY. THIS SHOULD CONTINUE THE FOG AND STRATUS OVER THE NEARSHORE WATERS THROUGH AT LEAST EARLY AFTERNOON. THE BETTER CHANCE FOR THUNDERSTORMS WILL COME LATER SUNDAY NIGHT THROUGH TUE NIGHT AS A MID LEVEL SHORTWAVE VERY SLOWLY TRACKS THROUGH MN AND WI. THE LOW LEVEL JET WILL POINT INTO SOUTHERN WI LATE SUNDAY NIGHT INTO MONDAY MORNING...WHICH WILL ALSO BE COINCIDENT WITH THE HIGH PRECIPITABLE WATER VALUES. BY MONDAY AND MONDAY NIGHT...THE MID LEVEL TROUGH WILL BE MOVING OVERHEAD ALONG WITH A SURFACE LOW PRESSURE TROUGH. RAIN AND THUNDERSTORMS ARE MOST LIKELY DURING THIS PERIOD. TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM. SURFACE HIGH PRESSURE WILL SETTLE OVER LAKE SUPERIOR LATER NEXT WEEK. ZONAL MID LEVEL FLOW AND AN 850MB FRONT STATIONED APPROX OVER SOUTHWEST WI WILL ALLOW FOR MORE SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT...ESPECIALLY IN SOUTH CENTRAL WI INLAND FROM THE LAKE. BEST CHANCE FOR PRECIP WILL BE EACH AFTERNOON. THERE ARE STILL TIMING AND COVERAGE DIFFERENCES BETWEEN THE MODELS. STAY TUNED. EASTERLY WINDS WILL KEEP LAKESHORE TEMPS COOLER. INLAND TEMPS ARE EXPECTED IN THE UPPER 70S. AVIATION/12Z TAFS/... A VERY DIFFICULT FORECAST INDEED. THE COOL EASTERLY FLOW OFF THE LAKE HAS COMBINED WITH THE MOIST AIRMASS IN PLACE THE LAST FEW DAYS...RESULTING IN A HUGE LOWER STRATUS DECK THAT COVERS MUCH OF ERN WISCONSIN AND NRN IL. IT/S CONSISTENTLY 200-300 AGL ACROSS THE AREA. THE LATEST AMDAR AIRCRAFT AND RAP SOUNDING SHOW THIS TO BE ABOUT 2-2.5KFT THICK. THE RAP MIXES IT OUT IN THE MILWAUKEE AREA BY AROUND 17-18Z THIS AFTERNOON...SO IT SHOULD HANG IN TIGHT THROUGH THE MORNING. THE EROSION AT KMSN IS AROUND 15Z. ONCE IT STARTS TO OPEN UP...IT WILL LIKELY LIFT INTO TO STRATOCU DECK BEFORE SCATTERING OUT. THE FOG/LOWER VSBYS SHOULD IMPROVE AFTER SUNRISE...AS WE START TO HEAT THINGS UP AND PUT A LITTLE DISTANCE BETWEEN THE TEMP AND DEWPOINT. THEN WE HAVE THE CHANCE FOR SHOWERS AND THUNDERSTORMS. THE BEST CHANCE FOR ANY STORMS LOOKS TO BE FROM ABOUT 20Z-01Z...OR TRADITIONAL PEAK HEATING. THERE WILL BE A WEAK FRONTAL BOUNDARY IN THE AREA THAT MAY ACT AS A FOCUS FOR THUNDERSTORM DEVELOPMENT. WE WILL BE IN A WEAK FLOW...MODERATELY UNSTABLE ENVIRONMENT THIS AFTERNOON...SO THERE IS PLENTY OF UNCERTAINTY. MORE FOG IS EXPECTED TONIGHT AS A BACKDOOR COLD FRONT SWEEPS DOWN THE LAKE AS WEAK LOW PRESSURE SCOOTS EAST. OF COURSE THIS MEANS MORE FOG AND POSSIBLY LOWER STRATUS AGAIN TONIGHT. MARINE... DENSE FOG IS EXPECTED THROUGH ABOUT MID MORNING. THE NEARSHORE AREAS MAY REMAIN IN A LIGHT FOG THROUGH THE DAY WITH MORE DENSE FOG POSSIBLE TONIGHT AS A COLD FRONT MOVES SOUTH DOWN THE LAKE SHORE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...DENSE FOG ADVISORY UNTIL 10 AM CDT SUNDAY FOR LMZ643>646. && $$ UPDATE...WOOD TODAY/TONIGHT AND AVIATION/MARINE...DAVIS SUNDAY THROUGH FRIDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 AM CDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1137 AM CDT SAT JUN 21 2014 REMNANT MCV FROM LAST NIGHTS CONVECTION FURTHER SOUTHWEST IS CURRENTLY TRACKING EAST ACROSS NORTHEAST IOWA/SOUTHWEST WISCONSIN. THIS HAS LEAD TO MUCH MORE CLOUD COVER AND SOME LIGHT RAIN SHOWERS ALONG THE MISSISSIPPI RIVER. 16Z RAP ANALYSIS SHOWS THE BETTER SB/MLCAPE CHANNEL RUNNING OUT AHEAD OF THIS MCV INTO SOUTHWEST/WEST CENTRAL WISCONSIN WITH IT BULLSEYED ON THE DELLS. THE MAIN CONVECTIVE CHANCES WILL BE OVER THE NEXT FEW HOURS BEFORE THIS FEATURE MOVES OFF TO THE EAST BY MID AFTERNOON. ONCE IT DOES MOVE OFF TO THE EAST...IT APPEARS THAT WE WILL SEE A DRY PERIOD GOING THROUGH TONIGHT AS A RIDGE OF HIGH PRESSURE MOVES IN WITH DRIER/STABLE AIR. THUS...HAVE ADJUSTED TRENDS TO BE CLOUDIER/RAINIER THIS MORNING/EARLY AFTERNOON AND THEN DROPPED CHANCES FOR PRECIPITATION FOR LATE THIS AFTERNOON/EARLY EVENING. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 316 AM CDT SAT JUN 21 2014 MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD. REGIONAL RADARS SHOWING A CONVECTIVE COMPLEX THIS MORNING OVER SOUTHWEST IOWA INTO SOUTHERN NEBRASKA. MOVEMENT OF THE ACTIVITY IS SLOWLY TO THE SOUTH/SOUTHEAST AND EXPECT THAT THIS WILL NOT IMPACT THE FORECAST AREA THIS MORNING. OTHER SHOWERS HAVE DEVELOPED THIS MORNING OVER NORTH CENTRAL WISCONSIN ALONG THE LEADING EDGE OF A WEAK BOUNDARY THAT HAS PUSHED IN FROM THE EAST. AS THE FLOW AHEAD OF THIS BOUNDARY BECOMES MORE SOUTH TO SOUTHWEST...ANTICIPATE THAT IT WILL START TO RETREAT WITH ANY SHOWERS ALONG MOVING OUT OF THE AREA BY MID MORNING. AFTER THAT...A FAIR AMOUNT OF UNCERTAINTY ON HOW THE REST OF THE DAY WILL PLAY OUT. THE 21.00Z NAM SUGGESTS A WEAK SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA THIS AFTERNOON AND EVENING WHILE THE 21.00Z GFS REALLY DOES NOT SHOW THIS FEATURE. LOOKING AT THE WATER VAPOR IMAGERY...IT DOES SUGGEST THERE COULD BE A WEAK WAVE COMING ACROSS THE DAKOTAS SIMILAR TO WHAT THE NAM INDICATES. WHETHER THIS WAVE WILL PRODUCE ANY CONVECTION IS QUESTIONABLE AS WELL. THE NAM ONLY SHOWS SOME WEAK PV ADVECTION IN THE 500-300 MB LAYER WITH LITTLE OR NO MOISTURE TRANSPORT INTO THE REGION. DESPITE THIS...IT DEVELOPS SOME CONVECTION ACROSS IOWA WHICH IS SIMILAR TO WHAT THE 21.00Z ECMWF SHOWS. THE GFS...DESPITE NOT HAVING THE WAVE...BLOWS UP EVEN MORE CONVECTION OVER MUCH OF THE AREA. THE 21.00Z HI-RES ARW SUGGESTS THAT ANY CONVECTION SHOULD DEVELOP SOUTHEAST OF THE AREA IN CONJUNCTION WITH THE MCV THAT MOVES OUT OF THE ONGOING IOWA CONVECTION. WILL JUST CARRY SOME 20 TO 30 PERCENT AFTERNOON RAIN CHANCES WITH THE HIGHER CHANCES ACROSS THE SOUTH AND EAST SECTIONS TO FAVOR THE NAM AND ARW SOLUTIONS. FAIRLY GOOD AGREEMENT THAT A STRONGER SHORT WAVE TROUGH WILL CROSS THE ROCKIES IN THE ZONAL FLOW AND MOVE ACROSS THE UPPER MIDWEST LATE TONIGHT THROUGH SUNDAY. SOME DIFFERENCES WITH THE TIMING OF THIS WAVE WITH THE NAM FASTER TO BRING IT IN THAN THE GFS OR ECMWF. THIS WAVE SHOULD BE ABLE TO PRODUCE SOME WEAK TO MODERATE PV ADVECTION IN THE 500-300 MB LAYER WITH 3 TO 6 UBAR/S OF UP GLIDE ON THE 305K ISENTROPIC SURFACE. EXPECT THAT THE AREA WILL BE CAUGHT IN BETWEEN SYSTEMS THIS EVENING WITH THE POSSIBILITY OF SOME DYING ACTIVITY FROM ANYTHING THAT DEVELOPS TODAY AND AN INCREASE OVERNIGHT AHEAD OF THE APPROACHING WAVE...ESPECIALLY ACROSS THE WEST. THE FORCING FROM THIS WAVE WILL CONTINUE TO SLOWLY INCREASE SUNDAY AS IT PUSHES A WEAK SURFACE BOUNDARY TOWARD THE AREA AS WELL. WILL SHOW THE RAIN CHANCES INCREASING TO ABOUT 40 PERCENT LATE TONIGHT ACROSS THE WEST AND UP TO 50 PERCENT FOR MUCH OF THE AREA SUNDAY. AS THIS SHORT WAVE TROUGH MOVES PAST THE AREA...THE GENERAL CONSENSUS AMONG THE MODELS IS THAT IT WILL BE QUICKLY FOLLOWED BY ANOTHER ONE FOR SUNDAY NIGHT AND MONDAY. THIS SHOULD PRODUCE ANOTHER ROUND OF WEAK PV ADVECTION...2-6 UBAR/S OF UP GLIDE ON THE 305K ISENTROPIC SURFACE ALONG WITH SOME WEAK FRONTOGENESIS IN THE 850-500 MB LAYER. THE WEAK SURFACE BOUNDARY THAT GETS PUSHED INTO THE AREA SUNDAY WILL STILL BE OVER THE REGION WITH THE NAM AND ECMWF SHOWING A WEAK SURFACE LOW MOVING ALONG THE BOUNDARY. THIS SHOULD BE ENOUGH TO PRODUCE A FAIR AMOUNT OF CONVECTION AND WILL CONTINUE WITH 40 TO 50 PERCENT RAIN CHANCES SUNDAY NIGHT INCREASING TO 60 PERCENT ACROSS THE SOUTHEAST FOR MONDAY. THE RISK FOR ORGANIZED SEVERE WEATHER LOOKS PRETTY LOW THROUGH MONDAY. WHILE DECENT CAPE SHOULD BE AVAILABLE EACH DAY...1000-2000 J/KG OF ML CAPE...THE WIND SHEAR LOOKS MARGINAL. THE 0-3KM SHEAR LOOKS TO BE 20 TO 30 KNOTS EACH DAY WHICH COULD SUPPORT SOME STRONG STORMS WITH A LITTLE BIT OF WIND POTENTIAL. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 316 AM CDT SAT JUN 21 2014 THE UNSETTLED PATTERN LOOKS TO CONTINUE THROUGH MUCH OF THE WEEK. AT SOME POINT...THE REMAINS OF THE UPPER LEVEL LOW CURRENTLY OVER MANITOBA WILL BECOME AN OPEN WAVE AND TRACK ACROSS THE UPPER MIDWEST. WITH THE WEAK ZONAL FLOW...THIS DOES NOT LOOK TO BE A QUICK PROCESS AND COULD TAKE MOST OF THE WEEK BEFORE IT FINALLY MOVES PAST THE REGION. THIS WILL CONTINUE TO PROVIDE A CHANCE OF RAIN TO THE AREA THROUGH THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 629 AM CDT SAT JUN 21 2014 WEAK LOW PRESSURE WILL EDGE TOWARDS THE TAF SITES TODAY AND MAY GENERATE AN ISOLATED SHOWER OR THUNDERSTORM. HOWEVER...CONFIDENCE ON ANY OF THIS ACTIVITY IMPACTING THE TAF SITES IS LOW SO HAVE NOT INCLUDED IN THE TAFS AT THIS TIME. OTHERWISE...PLAN ON VFR CONDITIONS TODAY. SCT TO BKN MID TO HIGH LEVEL CLOUDS ARE EXPECTED LATE THIS MORNING INTO THIS AFTERNOON WITH BASES IN THE 15-20KFT RANGE. NAM FORECAST SOUNDINGS ARE TRYING TO PRODUCE SOME LIGHT FOG AT KSLE LATE TONIGHT INTO EARLY SUNDAY MORNING SO WILL HAVE TO KEEP AN EYE ON THIS. TEMPERATURE AND DEWPOINT SPREADS APPEAR TO HIGH FOR FOG FORMATION SO WILL NOT INCLUDE IT IN THE TAF AT THIS TIME. && .HYDROLOGY... ISSUED AT 316 AM CDT SAT JUN 21 2014 MANY OF THE RIVERS ACROSS THE AREA REMAIN HIGH OR ARE FLOODING FROM ALL THE RECENT RAINS. LATEST INDICATIONS ARE THAT OUTSIDE OF THE MISSISSIPPI RIVER...A LOT OF THE RIVERS ARE CRESTING OR VERY CLOSE TO CRESTING AND SHOULD START TO GO DOWN HEADING THROUGH THE WEEKEND. CRESTS ON THE MISSISSIPPI RIVER ARE NOT EXPECTED TO START OCCURRING UNTIL ABOUT THE MIDDLE OF THE WEEK. SEE THE LATEST FLOOD STATEMENTS FOR SPECIFIC FORECAST INFORMATION. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...04 LONG TERM...04 AVIATION...WETENKAMP HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
339 AM CDT SAT JUN 21 2014 .SHORT TERM... TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM. WE HAVE A RATHER COMPLICATED FORECAST FOR TODAY AND TONIGHT. FOR STARTERS...A LARGE AREA OF LOW STRATUS/FOG AND COOL AIR HAS OVERSPREAD THE AREA FROM AN EASTERLY FLOW OFF LAKE MICHIGAN. THE EXACT DISSIPATION OF THIS DECK IS ALWAYS TRICKY AND WILL LIKELY IMPACT THE AIRSHOW SCHEDULED FOR THE LAKE SHORE OF MILWAUKEE TODAY. A DENSE FOG ADVISORY IS IN EFFECT FOR THE LAKE SHORE COUNTIES THROUGH 9 AM. IN GENERAL...VISIBILITIES ARE BETTER THAN 1/2 MILE...BUT AREA WEB CAMS SHOW SOME SPOTTY DENSE FOG...ESPECIALLY RIGHT ALONG THE LAKE. SO IT/S PRUDENT TO KEEP THIS GOING THROUGH MID MORNING. THE WESTERN EDGE OF THE STRATUS DECK...WEST OF MADISON EARLY THIS MORNING...IS DEFINING A STATIONARY FRONTAL BOUNDARY THAT EXTENDS UP TO A SURFACE LOW OVER EASTERN MINNESOTA. MEANWHILE...MANY OF THE MODELS ARE FIRING OFF SOME ELEVATED CONVECTION THAT PUSHES ACROSS THE CWA THIS MORNING. THIS IS IN ASSOCIATION WITH AN H7 TROF AND RIGHT ENTRANCE REGION OF A DEPARTING UPPER JET. AT THIS WRITING...THAT CONVECTION HASN/T STARTED YET AND CONFIDENCE ISN/T HIGH THAT IT WILL. SO SMALL POPS WILL COVER THAT FOR NOW AND WILL ADJUST IF IT STARTS TO SHOW ITS HAND...OR NOT. NOTHING WILL BE SURFACE BASED DUE TO THE RATHER DEEP CAPPING FROM THE COOLER FLOW OFF THE LAKE. FOR THIS AFTERNOON...THE MODEL SOUNDINGS SUGGEST THE STRATUS AND IT/S SUPPORTIVE LOW LEVEL INVERSION WILL MIX OUT BY AROUND NOON. THE SOUNDINGS SHOW UNCAPPED CAPE OF ABOUT 1500J/KG AVAILABLE THIS AFTERNOON AND WITH THE WEAK FRONTAL BOUNDARY STILL LINGERING...WE COULD SEE A FEW THUNDERSTORMS DEVELOP. DEEP LAYER BULK SHEAR IS ON THE WEAK SIDE...GENERALLY LESS THAN 30KTS...WITH PARAMETERS LOOKING BETTER TO THE SOUTH. IF WE GET DECENT DIFFERENTIAL HEATING ALONG THE EDGE OF THE STATUS...WE COULD SEE A STRONGER SURFACE BOUNDARY AND LLV CONVERGENCE. SPC HAS CLIPPED OUR FAR SOUTH WITH A SLIGHT RISK FOR SVR STORMS. ALTHOUGH IT APPEARS THE BEST CHANCE FOR THE STRONGEST STORMS WILL BE TO OUR SOUTH...THE HIRES ARW AND NMM MODELS BOTH SHOW SOMETHING ROLLING EAST ALONG THE STATE LINE. LOTS OF UNCERTAINTY WITH OVERALL WEAK FORCING WITHIN A MODERATELY UNSTABLE AIRMASS. THE COLDER LOW LEVEL STRATUS JUST COMPLICATES THINGS. SO WILL KEEP POPS ON THE LOWER SIDE WHICH MATCHES THE CONSENSUS OF THE MODELS AND THINKING OF SURROUNDING OFFICES. A BACKDOOR COLD FRONT IS EXPECTED TO DROP THROUGH THE AREA THIS EVENING IN THE WAKE OF A LOW PRESSURE SYSTEM SCOOTING EAST. THIS SHOULD SET THE STAGE FOR MORE FOG AND POSSIBLE LOW CLOUDS. && .AVIATION/12Z TAFS/... A VERY DIFFICULT FORECAST INDEED. THE COOL EASTERLY FLOW OFF THE LAKE HAS COMBINED WITH THE MOIST AIRMASS IN PLACE THE LAST FEW DAYS...RESULTING IN A HUGE LOWER STRATUS DECK THAT COVERS MUCH OF ERN WISCONSIN AND NRN IL. IT/S CONSISTENTLY 200-300 AGL ACROSS THE AREA. THE LATEST AMDAR AIRCRAFT AND RAP SOUNDING SHOW THIS TO BE ABOUT 2-2.5KFT THICK. THE RAP MIXES IT OUT IN THE MILWAUKEE AREA BY AROUND 17-18Z THIS AFTERNOON...SO IT SHOULD HANG IN TIGHT THROUGH THE MORNING. THE EROSION AT KMSN IS AROUND 15Z. ONCE IT STARTS TO OPEN UP...IT WILL LIKELY LIFT INTO TO STRATOCU DECK BEFORE SCATTERING OUT. THE FOG/LOWER VSBYS SHOULD IMPROVE AFTER SUNRISE...AS WE START TO HEAT THINGS UP AND PUT A LITTLE DISTANCE BETWEEN THE TEMP AND DEWPOINT. THEN WE HAVE THE CHANCE FOR SHOWERS AND THUNDERSTORMS. THE BEST CHANCE FOR ANY STORMS LOOKS TO BE FROM ABOUT 20Z-01Z...OR TRADITIONAL PEAK HEATING. THERE WILL BE A WEAK FRONTAL BOUNDARY IN THE AREA THAT MAY ACT AS A FOCUS FOR THUNDERSTORM DEVELOPMENT. WE WILL BE IN A WEAK FLOW...MODERATELY UNSTABLE ENVIRONMENT THIS AFTERNOON...SO THERE IS PLENTY OF UNCERTAINTY. MORE FOG IS EXPECTED TONIGHT AS A BACKDOOR COLD FRONT SWEEPS DOWN THE LAKE AS WEAK LOW PRESSURE SCOOTS EAST. OF COURSE THIS MEANS MORE FOG AND POSSIBLY LOWER STRATUS AGAIN TONIGHT. .LONG TERM... SUNDAY THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE MEDIUM. THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE DAY SUNDAY WITH WEAK 850MB FRONTOGENESIS AND 700 MB UPWARD MOTION. FORECAST SOUNDINGS FOR MADISON SHOW BUILDING CAPE THROUGH THE AFTERNOON WITH NO CAP. HOWEVER...LOW POPS BECAUSE WE MIGHT LACK A TRIGGER FOR ANY THUNDERSTORMS TO DEVELOP DUE TO MID LEVEL RIDGING OVERHEAD. IF THUNDERSTORMS DEVELOP...THE SHEAR IS WEAK SO NOT LOOKING FOR SEVERE STORMS DURING THE DAY. NEAR THE LAKE...WINDS WILL CONTINUE TO BE LIGHT AND EASTERLY ON SUNDAY. THIS SHOULD CONTINUE THE FOG AND STRATUS OVER THE NEARSHORE WATERS THROUGH AT LEAST EARLY AFTERNOON. THE BETTER CHANCE FOR THUNDERSTORMS WILL COME LATER SUNDAY NIGHT THROUGH TUE NIGHT AS A MID LEVEL SHORTWAVE VERY SLOWLY TRACKS THROUGH MN AND WI. THE LOW LEVEL JET WILL POINT INTO SOUTHERN WI LATE SUNDAY NIGHT INTO MONDAY MORNING...WHICH WILL ALSO BE COINCIDENT WITH THE HIGH PRECIPITABLE WATER VALUES. BY MONDAY AND MONDAY NIGHT...THE MID LEVEL TROUGH WILL BE MOVING OVERHEAD ALONG WITH A SURFACE LOW PRESSURE TROUGH. RAIN AND THUNDERSTORMS ARE MOST LIKELY DURING THIS PERIOD. TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM. SURFACE HIGH PRESSURE WILL SETTLE OVER LAKE SUPERIOR LATER NEXT WEEK. ZONAL MID LEVEL FLOW AND AN 850MB FRONT STATIONED APPROX OVER SOUTHWEST WI WILL ALLOW FOR MORE SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT...ESPECIALLY IN SOUTH CENTRAL WI INLAND FROM THE LAKE. BEST CHANCE FOR PRECIP WILL BE EACH AFTERNOON. THERE ARE STILL TIMING AND COVERAGE DIFFERENCES BETWEEN THE MODELS. STAY TUNED. EASTERLY WINDS WILL KEEP LAKESHORE TEMPS COOLER. INLAND TEMPS ARE EXPECTED IN THE UPPER 70S. && .AVIATION/12Z TAFS/... A VERY DIFFICULT FORECAST INDEED. THE COOL EASTERLY FLOW OFF THE LAKE HAS COMBINED WITH THE MOIST AIRMASS IN PLACE THE LAST FEW DAYS...RESULTING IN A HUGE LOWER STRATUS DECK THAT COVERS MUCH OF ERN WISCONSIN AND NRN IL. IT/S CONSISTENTLY 200-300 AGL ACROSS THE AREA. THE LATEST AMDAR AIRCRAFT AND RAP SOUNDING SHOW THIS TO BE ABOUT 2-2.5KFT THICK. THE RAP MIXES IT OUT IN THE MILWAUKEE AREA BY AROUND 17-18Z THIS AFTERNOON...SO IT SHOULD HANG IN TIGHT THROUGH THE MORNING. THE EROSION AT KMSN IS AROUND 15Z. ONCE IT STARTS TO OPEN UP...IT WILL LIKELY LIFT INTO TO STRATOCU DECK BEFORE SCATTERING OUT. THE FOG/LOWER VSBYS SHOULD IMPROVE AFTER SUNRISE...AS WE START TO HEAT THINGS UP AND PUT A LITTLE DISTANCE BETWEEN THE TEMP AND DEWPOINT. THEN WE HAVE THE CHANCE FOR SHOWERS AND THUNDERSTORMS. THE BEST CHANCE FOR ANY STORMS LOOKS TO BE FROM ABOUT 20Z-01Z...OR TRADITIONAL PEAK HEATING. THERE WILL BE A WEAK FRONTAL BOUNDARY IN THE AREA THAT MAY ACT AS A FOCUS FOR THUNDERSTORM DEVELOPMENT. WE WILL BE IN A WEAK FLOW...MODERATELY UNSTABLE ENVIRONMENT THIS AFTERNOON...SO THERE IS PLENTY OF UNCERTAINTY. MORE FOG IS EXPECTED TONIGHT AS A BACKDOOR COLD FRONT SWEEPS DOWN THE LAKE AS WEAK LOW PRESSURE SCOOTS EAST. OF COURSE THIS MEANS MORE FOG AND POSSIBLY LOWER STRATUS AGAIN TONIGHT. && .MARINE... DENSE FOG IS EXPECTED THROUGH ABOUT MID MORNING. THE NEARSHORE AREAS MAY REMAIN IN A LIGHT FOG THROUGH THE DAY WITH MORE DENSE FOG POSSIBLE TONIGHT AS A COLD FRONT MOVES SOUTH DOWN THE LAKE SHORE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ052-060- 066-071-072. LM...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR LMZ643>646. && $$ TODAY/TONIGHT AND AVIATION/MARINE...DAVIS SUNDAY THROUGH FRIDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1149 PM CDT FRI JUN 20 2014 .UPDATE... ISSUED AT 958 PM CDT FRI JUN 20 2014 FOR NO WEATHER IN THE FORECAST AREA...THERE SURE IS SOME ACTION AROUND US IN EVERY DIRECTION. TO THE EAST...HAVE ADJUSTED FORECAST FOR THE WESTWARD MOVING FRONT WHICH IS MARKED BY LOW CLOUD AND SOME NEAR 1 MILE VISIBILITIES. I KNOW THE SOLSTICE IS AROUND SUNRISE...BUT THAT IS TOO MUCH OF A WINTER LOOK TOO SOON. EASTERLY FLOW IS MAXIMIZING NOW THROUGH JUST AFTER MIDNIGHT AND SHOULD BEGIN TO VEER TOWARD SE-S LATER AS LOW PRESSURE APPROACHES WI. HAVE BROUGHT CLOUDS TO ABOUT KEAU-KDLL LINE AND LOWERED TEMPERATURES AND DEWPOINTS OVERNIGHT. HAVE NOT ADDED FOG YET BUT MAY NEED TO IF VSBYS ARE GOING TO GO LESS THAN 1 MILE. TO THE SOUTHWEST...CONVECTION IS STAYING BEHAVED AND FEEDING OFF LOW-LEVEL MOISTURE CONVERGENCE INTO SOUTHERN IA PER RAP MODEL GUIDANCE. THIS TREND SHOULD CONTINUE. HOWEVER...MOISTURE IN LOW- LEVELS IS DOING AN END-AROUND WITH W-SWRLY 850-925MB FLOW ACROSS NRN IA AND SRN MN EASTWARD...WHICH WILL INCREASE THE LOW-LEVEL DEWPOINTS BY 4C OR SO WITH TROUGH MOVING THROUGH...WARM FRONTAL. ALTHOUGH RAP FORECASTS SEEM TO INDICATE T/TD ARE STILL SOME 3C FROM LOW-LEVEL SATURATION...THERE IS SOME CONVERGENCE AND ELEVATED CAPE SHOULD SATURATION OCCUR IN THAT LAYER...WITH NO CAP. SO...OVERNIGHT THERE IS A CHANCE FOR A POP-UP SHOWER OR STORM IN THE 06-12Z TIME FRAME. SOME HI-RES CONVECTIVE ALLOWING MODELS SUGGEST THIS WITH SOME ECHO SHOWING UP IN WI. SMALL RAIN CHANCES ARE IN FOR THAT POSSIBILITY /20-30/. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 344 PM CDT FRI JUN 20 2014 AT 3 PM...TWO BOUNDARIES WERE LOCATED ACROSS THE FORECAST AREA. THE FIRST OF THESE TWO EXTENDS FROM NEW RICHMOND /KRNH/ TO LA CROSSE WISCONSIN. BOTH THE RAP AND LAPS DATA SHOW 150 TO 200 J/KG OF SURFACE TO 3 KM CAPE...STRONG LAYER ENHANCED STRETCHING POTENTIAL...STEEP 0-2 KM LAPSE RATES /GREATER THAN 9 C/KM /...AND WEAK TO MODERATE SURFACE RELATIVE VORTICITY. THIS WOULD BE SUPPORTIVE OF NON-SUPERCELL TORNADOES. THESE CONDITIONS CONTINUE THROUGH 21.02Z. HOWEVER AT THIS TIME...IT LOOKS LIKE THE CONVERGENCE WILL NOT BE GREAT ENOUGH FOR THEIR DEVELOPMENT. A SECOND BOUNDARY LOOKS TO BE EITHER A DRY LINE OR A DIFFERENTIAL HEATING BOUNDARY ACROSS CENTRAL WISCONSIN. THERE WAS A BRIEF SHOWER AT WAUSAU. JUST LIKE THE PREVIOUS BOUNDARY...THE CONVERGENCE IS NOT THAT STRONG ALONG THE BOUNDARY. WITH 2 TO 3K SURFACE BASED CAPES...WILL HAVE TO MONITOR THIS AREA FOR DEVELOPMENT. FURTHER NORTHWEST...A SHORT WAVE TROUGH WAS MOVING ACROSS NORTHERN MINNESOTA. THIS SYSTEM WAS MOVING THROUGH AN AREA OF 1K SURFACE CAPES. THIS HAS RESULTED IN THE DEVELOPMENT OF SHOWERS AND STORMS. WITH THE RAP SHOWING EFFECTIVE SHEAR GREATER THAN 40 KNOTS...AREAS NORTH OF INTERSTATE 94 WILL HAVE TO BE MONITORED FOR THE POTENTIAL OF SEVERE WEATHER. THERE IS A BOUNDARY NORTH OF PHILLIPS WISCONSIN. THIS COULD AID IN THE DEVELOPMENT OF A FEW TORNADOES. MEANWHILE FURTHER SOUTH...THE THREATS WILL BE LARGE HAIL AND DAMAGING WINDS. THIS MAY AFFECT CLARK AND TAYLOR COUNTIES LATE THIS AFTERNOON AND EVENING...BUT THIS IS HIGHLY DEPENDENT ON WHETHER STORMS CAN EVEN DEVELOP. MANY OF THE MESO MODELS SUGGEST THAT THIS WILL NOT BE THE CASE. FINALLY...AN AREA OF SHOWERS AND STORMS ARE DEVELOPING AHEAD OF A SHORT WAVE TROUGH MOVING OUT OF CENTRAL NEBRASKA. A FEW OF THESE STORMS HAVE ALREADY BECOME SEVERE. THE GFS...ECMWF...AND ARW SUGGEST THAT THESE SUPERCELLS WILL DEVELOP INTO A MESOSCALE CONVECTIVE COMPLEX WHICH WILL MOVE THROUGH OUR AREAS ALONG AND SOUTH OF INTERSTATE 90 BETWEEN 21.06Z AND 21.15Z. AT THIS TIME...IT LOOKS LIKE THE 0-3 KM AND 0-6 KM SHEAR WILL BE TOO WEAK FOR ANY SEVERE WEATHER WITH THIS COMPLEX. ONE THING THAT WILL HAVE TO WATCHED IS THAT THE HOP WRF AND HRRR SUGGEST THAT THIS COMPLEX MAY DIVE SOUTHEAST TOWARD THE BETTER INSTABILITY ACROSS MISSOURI...SO WILL HAVE TO WATCH THIS CLOSELY LATE TONIGHT. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 344 PM CDT FRI JUN 20 2014 THIS PART OF THE FORECAST IS GREATLY COMPLICATED DUE TO ZONAL FLOW ALOFT. THE EXTENDED MODELS ARE SHOWING VARYING TIMES AND STRENGTHS OF SHORT WAVES EMBEDDED IN THIS FLOW. OVERALL...THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS LOOKS TO BE FROM SUNDAY NIGHT THROUGH MONDAY AS A SHORT WAVE TROUGH MOVES THROUGH THE CENTRAL PLAINS AND MID MISSISSIPPI RIVER VALLEY...AND FROM TUESDAY THROUGH WEDNESDAY AS A CANADIAN COLD FRONT DROPS INTO THE AREA. THIS FRONT WILL LIKELY INCREASE THE SHEAR ACROSS THE AREA FOR THE POTENTIAL OF SEVERE WEATHER. HOWEVER THERE ARE UNCERTAINTIES ON HOW FAR SOUTH THIS FRONT WILL GET DUE TO THE ZONAL FLOW. AS A RESULT...STAYED CLOSE TO THE MODEL CONSENSUS FOR NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1150 PM CDT FRI JUN 20 2014 THUNDERSTORM ACTIVITY OVER IOWA WILL KEEP A STEADY FLOW OF THICK CIRRUS OVERHEAD. A WEAK FLOW PATTERN OVERHEAD WITH LITTLE FOCUS OF LIFT NEAR THE TAF SITES MEANS A VFR FORECAST. THERE IS A VERY SMALL CHANCE OF ISOLATED SHOWER OR TSRA OVERNIGHT BUT NOT A LARGE ENOUGH CHANCE TO INCLUDE IN THE FORECAST. IT APPEARS THE THICK OVERCAST WILL LIMIT COOLING BUT WITH ONLY 6F REMAINING TO COOL AT KLSE...DECIDED TO LEAVE THE 5SM BR IN THE FORECAST. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
307 PM MDT SAT JUN 21 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 307 PM MDT SAT JUN 21 2014 STORMS HAVE DEVELOPED EARLY THIS AFTN OVER GOSHEN COUNTY AND HAVE MOVED INTO THE CENTRAL AND NORTHERN PANHANDLE. THEY HAVE STRUGGLED TO BECOME DISCRETE SO FAR DUE TO THE MARGINAL DEEP LAYER SHEAR (25-30 KTS) AND HAVE FORMED INTO LINES/CLUSTERS. SPC MESOANALYSIS SHOWS GOOD INSTABILITY WITH MLCAPES OF 1500-2000 J/KG OVER THE PANHANDLE. BELIEVE THAT THE MAIN SVR THREAT DURING THE AFTN WILL BE DAMAGING WINDS WITH THE HIGH LCLS AND DEEP BOUNDARY LAYER OVER THE PANHANDLE. LARGE HAIL IS LESS OF THE THREAT WITH THE MARGINAL DEEP LAYER SHEAR...HOWEVER MARGINALLY SVR HAIL WILL BE POSSIBLE. A SEVERE THUNDERSTORM WATCH WAS ISSUED FOR ALL OF THE NEBRASKA PANHANDLE THROUGH 03Z. ALL OF THIS STORM ACTIVITY IS OCCURING AHEAD OF A SHORTWAVE THAT IS CURRENTLY LOCATED OVER WESTERN COLORADO. THE HRRR MODEL SHOWS MOST STORMS PUSHING EAST OUT OF THE CWA BY AROUND 00Z. COLD FRONT BEHIND THE SHORTWAVE WILL PUSH ACROSS THE PLAINS LATE TONIGHT AND SUNDAY MORNING. WINDS ARE STILL NORTHERLY AT 18Z SUN AND THEN BECOME MORE NORTHEASTERLY DURING THE AFTN. MODELS HAVE DECREASED INSTABILITY A BIT OVER YESTERDAYS RUN WITH LI VALUES OF AROUND -3C IN LARAMIE/PLATTE COUNTIES AND EXTENDING EASTWARD ALONG THE COLORADO BORDER. STORMS SHOULD DEVELOP BY AFTN IN THE CONVERGENCE ALONG THE SOUTHERN LARAMIE RANGE...HOWEVER DO NOT BELIEVE THEY WILL BECOME SVR AS THEY PUSH EASTWARD. STORM COVERAGE WILL BE MORE LIMITED OVER THE PANHANDLE AS THE AIRMASS IS MORE STABLE POST FRONTAL. TEMPS WILL BE 10-15 DEGREES COOLER ON SUNDAY. FOR MONDAY SFC WINDS BECOME MORE SOUTHEASTERLY AND AIRMASS IS MORE UNSTABLE THAN SUNDAY IN AREAS NEAR THE COLORADO BORDER. THIS IS THE DAY AFTER THE FROPA...WHICH OFTEN TIMES LEADS TO A GREATER SVR THREAT. NORTHWESTERLY FLOW ALOFT IS STRONG ENOUGH...COMBINED WITH THE SOUTHEAST LLVL FLOW...TO PRODUCE 40-45 KTS OF DEEP LAYER SHEAR SO THERE WILL LIKELY BE SOME SVR POTENTIAL ON MONDAY IN AREAS ALONG INTERSTATE 80. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 307 PM MDT SAT JUN 21 2014 THE ACTIVE PATTERN WILL CONTINUE INTO NEXT WEEK AS ZONAL FLOW BECOMES MORE SOUTHWESTERLY BY THE END OF THE WEEK. BOTH THE GFS AND EURO SOLUTIONS CONTINUE TO ADVERTISE DAILY CHANCES OF AFTERNOON AND EVENING CONVECTION AS SOUTHEASTERLY LLVL RETURN FLOW PERSISTS ALL WEEK. THIS WILL RESULT IN PERSISTENT THETA-E RIDGING OVER MUCH OF THE CWFA THROUGH THE ENTIRE WEEK. TUESDAY WILL BE THE SECOND DAY POST-FRONTAL...WHICH WHEN COMBINED WITH 0-6KM SHEAR OF 40-50 KNOTS SHOULD SET THE STAGE FOR AN ACTIVE SEVERE WEATHER DAY. THE GREATEST THREAT WILL BE EAST OF THE LARAMIE RANGE. PROGD SBCAPES WILL FLARE TO BETWEEN 2000-3000 J/KG FOR WED AND THU...WHICH SHOULD BE MORE THAN ENOUGH TO COMPENSATE FOR SOMEWHAT LIGHTER VALUES OF DEEP LAYER SHEAR. WOULD EXPECT SEVERE POTENTIAL TO CONTINUE FOR BOTH WED AND THU MAINLY EAST OF THE LARAMIE RANGE AS WELL. TROUGH WILL SWING THROUGH ON FRIDAY...DRAGGING A PACIFIC FRONT THRU THE AREA WHICH WILL EFFECTIVELY SHUNT BEST INSTABILITY EAST OVER CENTRAL NEBRASKA FOR BOTH FRIDAY AND SATURDAY. AS A RESULT...EXPECT THUNDERSTORM CHANCES TO TURN MORE ISOLATED EARLY NEXT WEEKEND. TEMPERATURES WILL BE SEASONALLY PERSISTENT THROUGH THE PERIOD WITH 70S ON TUESDAY WARMING INTO THE 80S AT LOWER ELEVATIONS FOR THE REMAINDER OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING) ISSUED AT 1148 AM MDT SAT JUN 21 2014 MAIN CONCERN FOR THIS FORECAST CYCLE IS THE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING. THE KCYS RADAR IS ALREADY STARTING TO LIGHT UP WITH SHOWERS AND THUNDERSTORMS DEVELOPING BETWEEN KCYS AND KDGW. FOR NOW...HAVE KEPT VCTS IN THE TAFS GIVEN THE UNCERTAINTY IN TIMING AND PRECISE LOCATION. WILL CONTINUE TO MONTIOR THUNDERSTORM TRENDS THRU THE REST OF THE AFTERNOON MAINLY FOR AIRFIELDS TO THE EAST OF THE LARAMIE RANGE. CONVECTION WILL DISSIPATE BY AROUND SUNSET AS THE THUNDERSTORMS PUSH EAST TOWARDS CENTRAL NEBRASKA. A COLD FRONTAL WILL PUSH SOUTH THROUGH THE AREA TONIGHT...SO EXPECT WINDS TO TURN NORTHERLY ALONG WITH POTENTIALLY A PERIOD OF MVFR CIGS AT KCDR/KAIA. NORTHERLY WINDS WILL TURN GUSTY LATE SUNDAY MORNING WITH ANOTHER ROUND OF AFTERNOON THUNDERSTORMS EXPECTED JUST BEYOND THIS TAF CYCLE FOR SUNDAY. && .FIRE WEATHER... ISSUED AT 307 PM MDT SAT JUN 21 2014 MINIMAL FIRE WEATHER CONCERNS THROUGH EARLY NEXT WEEK. MINIMUM RELATIVE HUMIDITY VALUES WILL BE AROUND 15 PERCENT THIS AFTERNOON FOR AREAS TO THE WEST OF THE LARAMIE RANGE. WEST WINDS WILL GUST TO 20-25 MPH THROUGH EARLY EVENING. SINCE FUELS ARE STILL GREEN ENOUGH TO NOT SUPPORT FIRE GROWTH...NO CRITICAL FIRE WEATHER THREAT IS EXPECTED. COOLER TEMPERATURES ON SUNDAY THROUGH EARLY NEXT WEEK WILL CAUSE AFTERNOON HUMIDITY VALUES TO INCREASE TO THE 20-30 PERCENT RANGE FOR AREAS TO THE WEST OF THE LARAMIE RANGE. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON THROUGH THE MIDDLE OF NEXT WEEK...WITH COVERAGE HIGHEST TO THE EAST OF THE LARAMIE RANGE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...FINCH LONG TERM...HAHN AVIATION...HAHN FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1150 AM MDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1100 AM MDT SAT JUN 21 2014 NOT A WHOLE LOT OF CHANGES MADE TO THE AFTN GRIDS. WEAK SHORTWAVE IS SEEN ON WATER VAPOR IMAGERY OVER NORTHWEST COLORADO WITH WIDESPREAD MID TO HIGH LEVEL CLOUDS CURRENTLY OVER SOUTHEAST WY. A LITTLE WORRIED THAT THIS CLOUD COVER WILL LIMIT SFC HEATING AND INSTABILITY THIS AFTN...ALTHOUGH WHERE STRONG TO SVR TSTM POTENTIAL IS HIGHEST (NEBRASKA PANHANDLE) THERE HAS BEEN GOOD WARMING THROUGH THE MORNING. THE HRRR MODEL HAS BEEN CONSISTENT AT SHOWING A LARGE AREA OF SHOWERS AND EMBEDDED TSTMS OVER THE PANHANDLE BETWEEN 22-01Z...WITH A MULTICELL APPEARANCE. WILL CONTINUE THE MENTION OF SLIGHT RISK OF SVR STORMS IN THE HWO...ALTHOUGH BULK SHEAR LOOKS A BIT MARGINAL AT 30-35 KTS FOR MORE DISCRETE SUPERCELLS. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 312 AM MDT SAT JUN 21 2014 GLOBAL MODELS AND CURRENT WATER VAPOR IMAGERY SHOW A SHORTWAVE APPROACHING FROM THE SOUTHWEST THAT IS PROGGED TO MOVE ACROSS OUR AREA DURING THE AFTERNOON/EVENING HOURS TODAY. AT THE SURFACE...WE NOTE A WELL DEFINED DRYLINE THAT EXTENDS FROM JUST NORTHWEST OF CHADRON TO JUST EAST OF CHEYENNE. EAST OF THE DRYLINE MUCAPES ARE RUNNING 400-800 J/KG ALREADY AND EXPECT BY THIS AFTERNOON WE WILL SEE ENOUGH DEEP LAYERED INSTABILITY TO LIGHT OFF A FEW STRONG TO SEVERE STORMS OVER THE NEBRASKA PANHANDLE WITH CAPES APPROACHING 2500 J/KG AND 1-6KM BULK SHEAR 25 TO 30 KTS ACROSS THE NORTHERN NEBRASKA PANHANDLE...SUGGESTING THAT A FEW STORMS COULD START TAKING ON SUPERCELL CHARACTERISTICS AS THEY MOVE EAST OUT OF EASTERN WYOMING INTO NORTHWESTERN NEBRASKA. MODEL AND OBSERVED SOUNDING DATA SHOW JUST ENOUGH OF A MIDLEVEL CAP TO HOLD BACK CONVECTION UNTIL THE MID AFTERNOON HOURS...THEN BY 3 PM WE EXPECT TO SEE SCATTERED STORMS INITIATING EAST OF A LUSK TO CHEYENNE LINE...STRENGTHENING AS THEY MOVE EASTWARD INTO THE DEEPER MOISTURE AND ZONE OF HIGHER INSTABILITY THROUGH LATE AFTERNOON INTO THE EVENING HOURS. MAIN CONCERN FOR SEVERE STORMS IMPACTS TODAY IS LARGE HAIL AND DAMAGING DOWNBURST WINDS IN EXCESS OF 60 MPH...MAINLY EAST OF A LINE FROM LUSK TO SIDNEY...ALTHOUGH GREATEST POTENTIAL FOR VERY LARGE HAIL... HIGHER DOWNDRAFT WINDS AND TO A LESSER DEGREE TORNADOES WILL BE FARTHER TO THE EAST/NORTHEAST INTO SOUTH DAKOTA AND NORTHERN NEBRASKA WHERE SHEAR VALUES FOR ORGANIZED UPDRAFTS WILL BE HIGHER. LOOKING FARTHER TO THE WEST TODAY...LATEST HIGH RESOLUTION RAPID REFRESH MODEL DOES HINT AT SOME WEAKER SHOWERS/STORMS FORMING UP IN THE EARLY AFTERNOON IN THE HIGHER TERRAIN OVER OUR WESTERN ZONES. WE CONTINUE TO MAINTAIN SLIGHT CHANCE/CHANCE POPS FOR AFTERNOON SHOWERS AND STORMS IN THE WEST WITH THE EXCEPTION OF THE WESTERN-MOST AREAS OF CARBON COUNTY. ANOTHER BREEZY DAY EXPECTED ABOVE 8000 FT MSL WITH GUSTS TO 35 MPH POSSIBLE DURING THE PEAK MECHANICAL MIXING PERIOD OF MID MORNING THROUGH LATE AFTERNOON. WE EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ON SUNDAY AS A COLD FRONT SINKS SOUTHWARDS AND IS PROGGED IN THE MODELS TO BANK UP ALONG AND EAST OF THE LARAMIE RANGE BY LATE AFTERNOON. MOST OF THE STORMS SUNDAY SHOULD BE NOTED EAST OF A LINE FROM DOUGLAS TO CHEYENNE IN THE REGION OF DEEPER MOISTURE AND INSTABILITY...WITH LESS COVERAGE TO THE WEST. DEEP LAYERED INSTABILITY FOR STRONG UPDRAFTS LOOKS A LITTLE MORE LIMITED ON SUNDAY...HOWEVER BULK SHEAR VALUES ACROSS EASTERN WYOMING AND WESTERN NEBRASKA COULD GET UP TO NEAR 30 KTS...SO A SMALL POTENTIAL FOR A FEW STRONGER STORMS IS THERE. THE KEY THING WE WILL NEED TO WATCH FOR ON SUNDAY WILL BE THE POTENTIAL FOR STORMS TO RE-DEVELOP OR TRAIN GRADUALLY FROM NORTHWEST TO SOUTHEAST...MEANING SOME AREAS COULD SEE MULTIPLE ROUNDS OF RAINFALL. QUESTION IS JUST HOW FAR SOUTH WILL THE FRONTAL BOUNDARY GET AND IF WE WILL SEE ENHANCED BACK-BUILDING OF STORMS WITH EAST/SOUTHEAST SURFACE FLOW WITH 25-35 KT MIDLEVEL FLOW ABOVE IT. RIGHT NOW FORECAST CONFIDENCE AS TO IF OR WHERE ANY FLASH FLOODING WOULD OCCUR ON SUNDAY IS NOT NEAR HIGH ENOUGH TO WARRANT THE ISSUANCE OF A WATCH. FOR MONDAY...MORE SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS ARE EXPECTED FOR THE CENTRAL AND EASTERN ZONES IN THE REGION OF DEEPER MOISURE. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 312 AM MDT SAT JUN 21 2014 MODELS IN GENERALLY GOOD AGREEMENT WITH THE OVERALL PATTERN THROUGH MOST OF NEXT WEEK...ALTHOUGH SOME DIFFERENCES ARE NOTED BY DAY 7 REGARDING THE TIMING OF AN UNUSUALLY STRONG UPPER LEVEL TROUGH ACROSS THE PACIFIC NORTHWEST FOR THIS TIME OF THE YEAR. THE WEATHER PATTERNS APPEARS TO BE PRETTY ACTIVE NEXT WEEK AS A SERIES OF SHORTWAVE DISTURBANCES EMBEDDED WITHIN THE QUASI-ZONAL FLOW PUSH ACROSS THE FORECAST AREA EACH DAY THROUGH THURSDAY. A LOW LEVEL SURFACE BOUNDARY WILL BE THE PRIMARY FACTOR IN DETERMINING CONVECTION INITIATION EACH DAY DUE TO AMPLE LLVL CONVERGENCE AND ADDITIONAL INSTABILITY. THE BOUNDARY POSITION WILL FLUCTUATE BETWEEN THE CONTINENTAL DIVIDE AND ALONG THE I25 CORRIDOR THROUGH THE PERIOD...RESULTING IN SOME DIFFICULTY IN PINPOINTING WHERE THE HIGHEST POTENTIAL OF CONVECTION WILL BE ALONG WITH HEAVY RAINFALL. MODELS INDICATE THIS BOUNDARY WILL PUSH FURTHER WEST AS THE DAYTIME PROGRESSES...AND THEN RETREAT EASTWARD TOWARDS THE I25 CORRIDOR EARLY IN THE MORNING AND AROUND SUNRISE...WITH SURFACE OBS LIKELY SHOWING A WESTERLY WINDS AS IT RETREATS EASTWARD. THEREFORE...EACH DAY WILL BE SIMILAR WITH AT LEAST A SCATTERED COVERAGE OF SHOWERS AND TSTORMS EACH DAY FROM MONDAY EVENING THROUGH WEDNESDAY EVENING. 0-6 KM SHEAR WILL RANGE FROM 35 TO 45 KNOTS EACH DAY...SUGGESTING SOME STRONG TO MARGINALLY SEVERE TSTORMS EACH DAY THROUGH WEDNESDAY. ADJUSTED POP ALONG AND EAST OF THE LARAMIE RANGE WITH VALUES BETWEEN 30 TO 45 PERCENT...HIGHEST IN THE AFTERNOON AND EVENING HOURS. HOWEVER...WOULD NOT BE SURPRISED IF THESE STORMS OR SHOWERS LINGERED WELL INTO THE OVERNIGHT HOURS DUE TO AVAILABLE MOISTURE AND UPPER LEVEL DISTURBANCES MOVING OVER THE AREA. ON THURSDAY...MODELS SHOW THE UPPER LEVEL FLOW BECOMING MORE SOUTHWESTERLY AND INCREASING IN STRENGTH AHEAD OF A POTENT PACIFIC STORM SYSTEM MOVING ONSHORE. THIS WILL RESULT IN THE LLVL BOUNDARY...WHICH HAS ACTED SIMILAR TO A DRY LINE...FINALLY RETREATING A BIT FURTHER EASTWARD...LIMITING CONVECTION TO THE HIGH PLAINS WITH ONLY ISOLATED COVERAGE THURSDAY AFTERNOON. FRIDAY APPEARS TO BE A TRANSITIONAL DAY...WITH THE HIGHLY AMPLIFIED 00Z ECMWF SHOWING THE POTENT UPPER LEVEL TROUGH AND ASSOCIATED PACIFIC STORM SYSTEM MOVING ACROSS THE GREAT BASIN REGION AND INTO THE FORECAST AREA...BRINGING WIDESPREAD RAIN SHOWERS AND ISOLATED THUNDER ALONG WITH MUCH COOLER TEMPERATURES. THE GFS IS NOT AS AMPLIFIED AND IS CONSIDERABLY SLOWER WITH THE TROUGH...WITH A PLEASANT DAY SETTING UP OVER THE FORECAST AREA ON FRIDAY. BELOW NORMAL TEMPERATURES EARLY THIS WEEK WITH GRADUALLY WARM UP BY THE MIDDLE OF THE WEEK AS HIGHS INCREASE INTO THE 80S TO NEAR 90 BY THURSDAY AFTERNOON. LOWERED TEMPERATURES A FEW DEGREES ON FRIDAY WITH SOME UNCERTAINTY...BUT STILL NEAR NORMAL FOR THE TIME OF THE YEAR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING) ISSUED AT 1148 AM MDT SAT JUN 21 2014 MAIN CONCERN FOR THIS FORECAST CYCLE IS THE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING. THE KCYS RADAR IS ALREADY STARTING TO LIGHT UP WITH SHOWERS AND THUNDERSTORMS DEVELOPING BETWEEN KCYS AND KDGW. FOR NOW...HAVE KEPT VCTS IN THE TAFS GIVEN THE UNCERTAINTY IN TIMING AND PRECISE LOCATION. WILL CONTINUE TO MONTIOR THUNDERSTORM TRENDS THRU THE REST OF THE AFTERNOON MAINLY FOR AIRFIELDS TO THE EAST OF THE LARAMIE RANGE. CONVECTION WILL DISSIPATE BY AROUND SUNSET AS THE THUNDERSTORMS PUSH EAST TOWARDS CENTRAL NEBRASKA. A COLD FRONTAL WILL PUSH SOUTH THROUGH THE AREA TONIGHT...SO EXPECT WINDS TO TURN NORTHERLY ALONG WITH POTENTIALLY A PERIOD OF MVFR CIGS AT KCDR/KAIA. NORTHERLY WINDS WILL TURN GUSTY LATE SUNDAY MORNING WITH ANOTHER ROUND OF AFTERNOON THUNDERSTORMS EXPECTED JUST BEYOND THIS TAF CYCLE FOR SUNDAY. && .FIRE WEATHER... ISSUED AT 312 AM MDT SAT JUN 21 2014 STILL SEE MINIMAL FIRE WEATHER IMPACTS THROUGH THE WEEKEND. AFTERNOON HUMIDITY VALUES WILL DROP TO 10 TO 15 PERCENT FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE THIS AFTERNOON AND ON SUNDAY. WEST TO SOUTHWEST WINDS WILL OCCASIONALLY GUST TO 30 MPH IN THE HIGHER TERRAIN DURING THE PERIOD OF PEAK MECHANICAL MIXING BOTH AFTERNOONS. HOWEVER...NO CRITICAL FIRE WEATHER THREAT IS ANTICIPATED SINCE FUELS HAVE STILL NOT DRIED ENOUGH TO SUPPORT SIGNIFICANT FIRE GROWTH. WE ARE STILL EXPECTING COOLER TEMPERATURES SUNDAY INTO EARLY NEXT WEEK ALONG WITH A BETTER CHANCE OF WETTING RAINS...ESPECIALLY TO THE EAST OF THE LARAMIE RANGE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...FINCH SHORT TERM...GARMON LONG TERM...TJT AVIATION...HAHN FIRE WEATHER...GARMON
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1113 AM MDT SAT JUN 21 2014 .UPDATE... ISSUED AT 1100 AM MDT SAT JUN 21 2014 NOT A WHOLE LOT OF CHANGES MADE TO THE AFTN GRIDS. WEAK SHORTWAVE IS SEEN ON WATER VAPOR IMAGERY OVER NORTHWEST COLORADO WITH WIDESPREAD MID TO HIGH LEVEL CLOUDS CURRENTLY OVER SOUTHEAST WY. A LITTLE WORRIED THAT THIS CLOUD COVER WILL LIMIT SFC HEATING AND INSTABILITY THIS AFTN...ALTHOUGH WHERE STRONG TO SVR TSTM POTENTIAL IS HIGHEST (NEBRASKA PANHANDLE) THERE HAS BEEN GOOD WARMING THROUGH THE MORNING. THE HRRR MODEL HAS BEEN CONSISTENT AT SHOWING A LARGE AREA OF SHOWERS AND EMBEDDED TSTMS OVER THE PANHANDLE BETWEEN 22-01Z...WITH A MULTICELL APPEARANCE. WILL CONTINUE THE MENTION OF SLIGHT RISK OF SVR STORMS IN THE HWO...ALTHOUGH BULK SHEAR LOOKS A BIT MARGINAL AT 30-35 KTS FOR MORE DISCRETE SUPERCELLS. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 312 AM MDT SAT JUN 21 2014 GLOBAL MODELS AND CURRENT WATER VAPOR IMAGERY SHOW A SHORTWAVE APPROACHING FROM THE SOUTHWEST THAT IS PROGGED TO MOVE ACROSS OUR AREA DURING THE AFTERNOON/EVENING HOURS TODAY. AT THE SURFACE...WE NOTE A WELL DEFINED DRYLINE THAT EXTENDS FROM JUST NORTHWEST OF CHADRON TO JUST EAST OF CHEYENNE. EAST OF THE DRYLINE MUCAPES ARE RUNNING 400-800 J/KG ALREADY AND EXPECT BY THIS AFTERNOON WE WILL SEE ENOUGH DEEP LAYERED INSTABILITY TO LIGHT OFF A FEW STRONG TO SEVERE STORMS OVER THE NEBRASKA PANHANDLE WITH CAPES APPROACHING 2500 J/KG AND 1-6KM BULK SHEAR 25 TO 30 KTS ACROSS THE NORTHERN NEBRASKA PANHANDLE...SUGGESTING THAT A FEW STORMS COULD START TAKING ON SUPERCELL CHARACTERISTICS AS THEY MOVE EAST OUT OF EASTERN WYOMING INTO NORTHWESTERN NEBRASKA. MODEL AND OBSERVED SOUNDING DATA SHOW JUST ENOUGH OF A MIDLEVEL CAP TO HOLD BACK CONVECTION UNTIL THE MID AFTERNOON HOURS...THEN BY 3 PM WE EXPECT TO SEE SCATTERED STORMS INITIATING EAST OF A LUSK TO CHEYENNE LINE...STRENGTHENING AS THEY MOVE EASTWARD INTO THE DEEPER MOISTURE AND ZONE OF HIGHER INSTABILITY THROUGH LATE AFTERNOON INTO THE EVENING HOURS. MAIN CONCERN FOR SEVERE STORMS IMPACTS TODAY IS LARGE HAIL AND DAMAGING DOWNBURST WINDS IN EXCESS OF 60 MPH...MAINLY EAST OF A LINE FROM LUSK TO SIDNEY...ALTHOUGH GREATEST POTENTIAL FOR VERY LARGE HAIL... HIGHER DOWNDRAFT WINDS AND TO A LESSER DEGREE TORNADOES WILL BE FARTHER TO THE EAST/NORTHEAST INTO SOUTH DAKOTA AND NORTHERN NEBRASKA WHERE SHEAR VALUES FOR ORGANIZED UPDRAFTS WILL BE HIGHER. LOOKING FARTHER TO THE WEST TODAY...LATEST HIGH RESOLUTION RAPID REFRESH MODEL DOES HINT AT SOME WEAKER SHOWERS/STORMS FORMING UP IN THE EARLY AFTERNOON IN THE HIGHER TERRAIN OVER OUR WESTERN ZONES. WE CONTINUE TO MAINTAIN SLIGHT CHANCE/CHANCE POPS FOR AFTERNOON SHOWERS AND STORMS IN THE WEST WITH THE EXCEPTION OF THE WESTERN-MOST AREAS OF CARBON COUNTY. ANOTHER BREEZY DAY EXPECTED ABOVE 8000 FT MSL WITH GUSTS TO 35 MPH POSSIBLE DURING THE PEAK MECHANICAL MIXING PERIOD OF MID MORNING THROUGH LATE AFTERNOON. WE EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ON SUNDAY AS A COLD FRONT SINKS SOUTHWARDS AND IS PROGGED IN THE MODELS TO BANK UP ALONG AND EAST OF THE LARAMIE RANGE BY LATE AFTERNOON. MOST OF THE STORMS SUNDAY SHOULD BE NOTED EAST OF A LINE FROM DOUGLAS TO CHEYENNE IN THE REGION OF DEEPER MOISTURE AND INSTABILITY...WITH LESS COVERAGE TO THE WEST. DEEP LAYERED INSTABILITY FOR STRONG UPDRAFTS LOOKS A LITTLE MORE LIMITED ON SUNDAY...HOWEVER BULK SHEAR VALUES ACROSS EASTERN WYOMING AND WESTERN NEBRASKA COULD GET UP TO NEAR 30 KTS...SO A SMALL POTENTIAL FOR A FEW STRONGER STORMS IS THERE. THE KEY THING WE WILL NEED TO WATCH FOR ON SUNDAY WILL BE THE POTENTIAL FOR STORMS TO RE-DEVELOP OR TRAIN GRADUALLY FROM NORTHWEST TO SOUTHEAST...MEANING SOME AREAS COULD SEE MULTIPLE ROUNDS OF RAINFALL. QUESTION IS JUST HOW FAR SOUTH WILL THE FRONTAL BOUNDARY GET AND IF WE WILL SEE ENHANCED BACK-BUILDING OF STORMS WITH EAST/SOUTHEAST SURFACE FLOW WITH 25-35 KT MIDLEVEL FLOW ABOVE IT. RIGHT NOW FORECAST CONFIDENCE AS TO IF OR WHERE ANY FLASH FLOODING WOULD OCCUR ON SUNDAY IS NOT NEAR HIGH ENOUGH TO WARRANT THE ISSUANCE OF A WATCH. FOR MONDAY...MORE SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS ARE EXPECTED FOR THE CENTRAL AND EASTERN ZONES IN THE REGION OF DEEPER MOISURE. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 312 AM MDT SAT JUN 21 2014 MODELS IN GENERALLY GOOD AGREEMENT WITH THE OVERALL PATTERN THROUGH MOST OF NEXT WEEK...ALTHOUGH SOME DIFFERENCES ARE NOTED BY DAY 7 REGARDING THE TIMING OF AN UNUSUALLY STRONG UPPER LEVEL TROUGH ACROSS THE PACIFIC NORTHWEST FOR THIS TIME OF THE YEAR. THE WEATHER PATTERNS APPEARS TO BE PRETTY ACTIVE NEXT WEEK AS A SERIES OF SHORTWAVE DISTURBANCES EMBEDDED WITHIN THE QUASI-ZONAL FLOW PUSH ACROSS THE FORECAST AREA EACH DAY THROUGH THURSDAY. A LOW LEVEL SURFACE BOUNDARY WILL BE THE PRIMARY FACTOR IN DETERMINING CONVECTION INITIATION EACH DAY DUE TO AMPLE LLVL CONVERGENCE AND ADDITIONAL INSTABILITY. THE BOUNDARY POSITION WILL FLUCTUATE BETWEEN THE CONTINENTAL DIVIDE AND ALONG THE I25 CORRIDOR THROUGH THE PERIOD...RESULTING IN SOME DIFFICULTY IN PINPOINTING WHERE THE HIGHEST POTENTIAL OF CONVECTION WILL BE ALONG WITH HEAVY RAINFALL. MODELS INDICATE THIS BOUNDARY WILL PUSH FURTHER WEST AS THE DAYTIME PROGRESSES...AND THEN RETREAT EASTWARD TOWARDS THE I25 CORRIDOR EARLY IN THE MORNING AND AROUND SUNRISE...WITH SURFACE OBS LIKELY SHOWING A WESTERLY WINDS AS IT RETREATS EASTWARD. THEREFORE...EACH DAY WILL BE SIMILAR WITH AT LEAST A SCATTERED COVERAGE OF SHOWERS AND TSTORMS EACH DAY FROM MONDAY EVENING THROUGH WEDNESDAY EVENING. 0-6 KM SHEAR WILL RANGE FROM 35 TO 45 KNOTS EACH DAY...SUGGESTING SOME STRONG TO MARGINALLY SEVERE TSTORMS EACH DAY THROUGH WEDNESDAY. ADJUSTED POP ALONG AND EAST OF THE LARAMIE RANGE WITH VALUES BETWEEN 30 TO 45 PERCENT...HIGHEST IN THE AFTERNOON AND EVENING HOURS. HOWEVER...WOULD NOT BE SURPRISED IF THESE STORMS OR SHOWERS LINGERED WELL INTO THE OVERNIGHT HOURS DUE TO AVAILABLE MOISTURE AND UPPER LEVEL DISTURBANCES MOVING OVER THE AREA. ON THURSDAY...MODELS SHOW THE UPPER LEVEL FLOW BECOMING MORE SOUTHWESTERLY AND INCREASING IN STRENGTH AHEAD OF A POTENT PACIFIC STORM SYSTEM MOVING ONSHORE. THIS WILL RESULT IN THE LLVL BOUNDARY...WHICH HAS ACTED SIMILAR TO A DRY LINE...FINALLY RETREATING A BIT FURTHER EASTWARD...LIMITING CONVECTION TO THE HIGH PLAINS WITH ONLY ISOLATED COVERAGE THURSDAY AFTERNOON. FRIDAY APPEARS TO BE A TRANSITIONAL DAY...WITH THE HIGHLY AMPLIFIED 00Z ECMWF SHOWING THE POTENT UPPER LEVEL TROUGH AND ASSOCIATED PACIFIC STORM SYSTEM MOVING ACROSS THE GREAT BASIN REGION AND INTO THE FORECAST AREA...BRINGING WIDESPREAD RAIN SHOWERS AND ISOLATED THUNDER ALONG WITH MUCH COOLER TEMPERATURES. THE GFS IS NOT AS AMPLIFIED AND IS CONSIDERABLY SLOWER WITH THE TROUGH...WITH A PLEASANT DAY SETTING UP OVER THE FORECAST AREA ON FRIDAY. BELOW NORMAL TEMPERATURES EARLY THIS WEEK WITH GRADUALLY WARM UP BY THE MIDDLE OF THE WEEK AS HIGHS INCREASE INTO THE 80S TO NEAR 90 BY THURSDAY AFTERNOON. LOWERED TEMPERATURES A FEW DEGREES ON FRIDAY WITH SOME UNCERTAINTY...BUT STILL NEAR NORMAL FOR THE TIME OF THE YEAR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY) ISSUED AT 312 AM MDT SAT JUN 21 2014 LOW LEVEL MOISTURE IS CURRENTLY PUSHING FURTHER NORTH AND WEST EARLY THIS MORNING WITH DEWPOINTS IN THE UPPER 50S TO AROUND 60 ACROSS WESTERN NEBRASKA. LOW LEVEL MOISTURE TO CONTINUE INCREASING OVERNIGHT...SETTING THE STAGE FOR SHOWERS AND TSTORMS SATURDAY AFTERNOON MAINLY EAST OF THE LARAMIE RANGE. ACTIVITY WILL BEGIN AS RAIN SHOWERS WEST OF THE LARAMIE RANGE AROUND 18Z...AND EVENTUALLY PUSH EASTWARD TOWARDS KLAR...KCYS IN THE AFTERNOON. COLD FRONT STILL FORECAST TO MOVE SOUTHWARD ACROSS THE EAST SLOPES OF THE LARAMIE RANGE LATE SATURDAY NIGHT WITH UPSLOPE WINDS EAST OF THE FRONT. WOULD EXPECT THIS TIME FRAME TO BE THE BETTER CHANCE FOR MORE WIDESPREAD MVFR/IFR CONDITIONS. SO...TRENDED THE TAFS THAT WAY WITH LOWERING CLOUDS LATE IN THE 06Z TAF CYCLE. && .FIRE WEATHER... ISSUED AT 312 AM MDT SAT JUN 21 2014 STILL SEE MINIMAL FIRE WEATHER IMPACTS THROUGH THE WEEKEND. AFTERNOON HUMIDITY VALUES WILL DROP TO 10 TO 15 PERCENT FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE THIS AFTERNOON AND ON SUNDAY. WEST TO SOUTHWEST WINDS WILL OCCASIONALLY GUST TO 30 MPH IN THE HIGHER TERRAIN DURING THE PERIOD OF PEAK MECHANICAL MIXING BOTH AFTERNOONS. HOWEVER...NO CRITICAL FIRE WEATHER THREAT IS ANTICIPATED SINCE FUELS HAVE STILL NOT DRIED ENOUGH TO SUPPORT SIGNIFICANT FIRE GROWTH. WE ARE STILL EXPECTING COOLER TEMPERATURES SUNDAY INTO EARLY NEXT WEEK ALONG WITH A BETTER CHANCE OF WETTING RAINS...ESPECIALLY TO THE EAST OF THE LARAMIE RANGE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...FINCH SHORT TERM...GARMON LONG TERM...TJT AVIATION...TJT FIRE WEATHER...GARMON
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1042 PM MDT FRI JUN 20 2014 .UPDATE... ISSUED AT 931 PM MDT FRI JUN 20 2014 GRIDDED FORECASTS IN DECENT SHAPE FOR TONIGHT...AND HAVE MADE ONLY SOME MINOR CHANGES TO ACCOUNT FOR TRENDS AND THE PROGS OF THE 00Z MODEL GUIDANCE. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 345 PM MDT FRI JUN 20 2014 PRETTY QUIET AFTN WITH A DRY AIRMASS ACROSS THE CWA. CUMULUS DEVELOPMENT HAS LARGELY BEEN CONFINED TO NORTHEASTERN COLORADO AND STRETCHING NORTHEAST INTO CENTRAL NEBRASKA WHERE DEWPOINTS ARE IN THE UPPER 50S. MODELS DO NOT SHOW MOISTURE ADVECTING WESTWARD THROUGH THE EVENING...SO STORM CHANCES WILL BE QUITE SLIM. TEMPS ARE WARM THIS AFTN WITH THE CLEAR SKIES AND 700MB TEMPS AROUND 12C. ZONAL FLOW ALOFT WILL CONTINUE THROUGH MUCH OF THE WEEKEND. A SFC TROUGH WILL BE LOCATED ACROSS THE WESTERN NEBRASKA PANHANDLE ON SATURDAY AFTN. CONVERGENCE ALONG THE TROUGH WILL CAUSE TSTMS TO DEVELOP BY THE AFTN WITH GOOD INSTABILITY TO THE EAST (LI VALUES OF -4C). THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND NAM ON THE LOCATION OF THE BOUNDARY. THE FURTHER EAST GFS SOLN WOULD KEEP THE BEST STORM CHANCES TO THE EAST OF THE CWA WHEREAS THE NAM SHOWS HIGHER DEWPOINTS/GOOD INSTABILITY WELL WESTWARD TO THE WY-NE BORDER. THE SPC HAS MUCH OF THE PANHANDLE IN A SLIGHT RISK FOR SVR STORMS TOMORROW. DEEP LAYER SHEAR IS MARGINAL AT AROUND 30-35 KTS SO NOT CONFIDENT THAT WE WILL SEE A WIDESPREAD SVR EVENT. A WEAK SHORTWAVE WILL PUSH TO THE NORTH OF THE CWA ON SUNDAY THAT WILL CAUSE A COLD FRONT TO MOVE OVER THE PLAINS DURING THE MORNING. WILL SEE ABOUT A 10 DEGREE COOL DOWN ON SUNDAY BEHIND THE FRONT. BOTH THE GFS AND NAM INDICATE GOOD INSTABILITY ON SUN AFTN OVER THE PLAINS WITH LI VALUES OF -3C TO -5C. SOUTHEAST WY WILL SEE A MUCH BETTER CHANCE OF STORMS ON SUNDAY AFTN WITH THE INCREASED LLVL MOISTURE AND UPSLOPE SFC WINDS. CAN NOT RULE OUT STRONGER STORMS ON SUNDAY ALSO WITH BULK SHEAR AT AROUND 35 KTS. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 345 PM MDT FRI JUN 20 2014 A SEASONALLY ACTIVE PERIOD SHAPING UP AS A SERIES OF SHORTWAVES EMBEDDED WITHIN QUASI-ZONAL FLOW PUSH THRU THE CWA. EACH SHORTWAVE IS IMPOSSIBLE TO TIME AT THIS TEMPORAL RANGE. SFC BOUNDARY WILL BEGIN THE PERIOD NR THE DIVIDE WITH A SHORTWAVE TRAVERSING EAST. INSTABILITY POOLING IN THE VICINITY OF THE BOUNDARY WILL CONTRIBUTE TO LINGERING CONVECTION SUNDAY NIGHT. WEST/NORTHWEST FLOW WILL ENSUE MON/TUE AS UPSTREAM RIDGE TRIES TO DEVELOP AHEAD OF A TROUGH OVR THE PACNW. INSTABILITY REMAINS WITH PROGD SBCAPES OF 1000-1500 J/KG EACH DAY. DEEP LAYER SHEAR OF 35-50 KNOTS SUGGEST THE POTENTIAL FOR A FEW STORMS TO BECOME STRONG TO LOCALLY SEVERE BOTH DAYS. SO...KEPT IN CHANCES OF THUNDERSTORMS GOING WITH THE BEST COVERAGE FOR AREAS ALONG AND EAST OF THE LARAMIE RANGE. THE GFS IS MORE AGGRESSIVE IN AMPLIFYING THE RIDGE FOR THE LATTER HALF OF THE UPCOMING WEEK. IN THIS SCENARIO...CONVECTIVE CHANCES WOULD BE LESSER. THE ECMWF IS LESS AMPLIFIED...OFFERING A BETTER CHANCE OF THE TYPICAL ACTIVE AFTERNOON AND EVENINGS. SUSPECT THE ANSWER IS SOMEWHERE IN BETWEEN AND FOR NOW HAVE LESSENED COVERAGE FOR WEDNESDAY AND KEPT CONDITIONS DRY FOR THU/FRI. AS FOR TEMPERATURES...MONDAY WILL BE THE COOLEST DAY OF THE WEEK AS HIGHS REACH THE 70S. TEMPERATURES CLIMB BACK INTO THE 80S AT MOST LOCATIONS WED-FRI. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY EVENING) ISSUED AT 1037 PM MDT FRI JUN 20 2014 LOW LEVEL MOISTURE BEGINNING TO MAKE ITS WAY INTO THE SOUTHERN PANHANDLE THIS EVENING. IN FACT...THE LATEST HRRR GUIDANCE SHOWING IFR CONDITIONS HERE AT KCYS AFTER 08Z. NOT TOO SURE OF THAT HAPPENING AS WE ARE STILL PRETTY DRY...RH OF 48 PERCENT AT 1030PM...SO DID NOT FOLLOW THIS GUIDANCE. LOOK FOR LOW LEVEL MOISTURE TO CONTINUE INCREASING OVERNIGHT...SETTING THE STAGE FOR SHOWERS AND TSTMS SATURDAY AFTERNOON EAST OF THE LARAMIE RANGE. COLD FRONT STILL FORECAST TO MOVE TO THE EAST SLOPES OF THE LARAMIE RANGE LATE SATURDAY NIGHT WITH UPSLOPING WINDS EAST OF THE FRONT. WOULD EXPECT THIS TIME FRAME TO BE THE BETTER CHANCE FOR MORE WIDESPREAD MVFR/IFR CONDITIONS. SO...TRENDED THE TAFS THAT WAY WITH LOWERING CLOUDS LATE IN THE 06Z TAF CYCLE. && .FIRE WEATHER... ISSUED AT 345 PM MDT FRI JUN 20 2014 MINIMAL FIRE WEATHER CONCERNS THROUGH THE WEEKEND. AFTERNOON HUMIDITY VALUES WILL DROP TO AROUND 15 PERCENT FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE THIS AFTERNOON AND ON SATURDAY. WEST TO SOUTHWEST WINDS WILL OCCASIONALLY GUST TO 25 MPH BOTH AFTERNOONS. HOWEVER...NO CRITICAL FIRE WEATHER THREAT IS ANTICIPATED SINCE FUELS HAVE STILL NOT CURED ENOUGH TO SUPPORT FIRE GROWTH. COOLER TEMPERATURES WILL OCCUR ON SUNDAY AND INTO EARLY NEXT WEEK ALONG WITH A BETTER CHANCE OF WETTING RAINS...ESPECIALLY TO THE EAST OF THE LARAMIE RANGE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...RUBIN SHORT TERM...FINCH LONG TERM...HAHN AVIATION...CLAYCOMB FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
332 AM EDT Mon Jun 23 2014 .Near Term [Through Today]... A broken line of thunderstorms has gradually shifted southeast off the Florida Panhandle coast by 06Z. There are some indications in surface observations that there may be a subtle mesohigh just offshore, which would create a convergence zone roughly near the Panhandle coast early this morning. Additionally, MSAS analysis shows a surface trough extending in a west-east fashion just inland of the Gulf coast. Convection-allowing models that have been initialized at 00Z appear to give credence to these features as a potential convective focus this morning. Nearly all of the CAMs, regardless of whether or not they are resolving current offshore convection accurately, show some sort of convective development in the Florida Panhandle 12-16Z - filling in across the remainder of our Florida zones in the late morning and early afternoon. This also happens to coincide with a maximum in PWATs - as indicated by GOES blended TPW and RAP analysis. We included a region of 60% PoPs in the Florida Panhandle 12-18Z from Tallahassee and to the west. For the rest of the day, models indicate some scattered thunderstorms will remain possible but very few show more widespread coverage. Therefore, we opted for a broad 50% PoP in the afternoon hours. Given the possibility for an early start to convection, highs in the Florida zones may be closer to 90 degrees, with slightly higher values further inland in our Alabama and Georgia zones. .Short Term [Tonight Through Wednesday]... Ridging remains located off to the east of the region with a trough moving across the Tennessee River Valley on Tuesday. With the presence of this trough nearby and still plenty of deep layer moisture available, expect above normal storm coverage during the daytime hours. With more storm coverage, expect daytime highs to generally be in the lower 90s across the area. By Wednesday, most of the model guidance show deep layer moisture decreasing which should result in less storm coverage so will show slightly lower pops than on Tuesday. If some of the guidance is correct, additional downward adjustments in rain chances may be necessary. With mid level ridging trying to build back over the region by Wednesday and less storm coverage expected, temperatures will be warmer with highs in the mid 90s away from the coast. .Long Term [Wednesday Night Through Monday]... Much of the same for the extended range forecast as the local area will likely remain sandwiched between an upper ridge and upper trough, with only weak synoptic forcing. Most afternoons will be dominated by seabreeze convection. Rain chances will remain near average with high temperatures in the middle to upper 90s. && .Aviation... [Through 06Z Tuesday] Through 13Z, some patchy MVFR VIS in light fog will be possible, but otherwise VFR will prevail with multiple cloud layers. DHN has had a few instances of IFR/LIFR CIGS in recent hours, but this has not been sustained for lengthy periods of time. If that becomes the case, an amendment may become necessary there. Thunderstorm redevelopment is expected in the Florida Panhandle and Big Bend in the morning, especially 12-16Z. The most likely impacts from thunderstorms would be at ECP, TLH, and VLD. Scattered thunderstorms will be possible in the afternoon. +TSRA could produce some IFR VIS and brief gusty winds. && .Marine... A fairly typical summertime pattern will result in light winds and low seas throughout the next several days. && .Fire Weather... Red flag conditions are not expected. && .Hydrology... Rainfall totals for the next 5-7 days will range from 1 to 2 inches across the area. With all rivers below bank full stage, this rainfall is not expected to cause significant rises on area rivers. && .Preliminary Point Temps/PoPs... Tallahassee 90 73 91 72 94 / 60 30 40 20 40 Panama City 87 75 89 76 90 / 60 30 30 20 30 Dothan 91 72 91 72 94 / 50 40 50 30 40 Albany 93 72 91 72 93 / 50 40 60 30 40 Valdosta 92 71 91 71 94 / 50 40 50 30 40 Cross City 90 71 92 71 93 / 50 30 30 20 30 Apalachicola 87 74 89 75 90 / 60 30 30 20 30 && .TAE Watches/Warnings/Advisories... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...LAMERS SHORT TERM...GODSEY LONG TERM...HARRIGAN AVIATION...LAMERS MARINE...GODSEY FIRE WEATHER...LAMERS HYDROLOGY...BOLDEN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
348 AM CDT MON JUN 23 2014 .DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * POTENTIAL FOR IFR/LIFR CIGS AND/OR VSBY IN BR/FG/STRATUS FOR THE REMAINDER OF THE OVERNIGHT HOURS BECOMING LESS LIKELY AS THE ENVIRONMENT IS STIRRED UP BY ONGOING SHRA. * SHRA/TSRA POTENTIAL THIS AFTERNOON AND EVENING. KREIN //DISCUSSION...UPDATED 06Z... MAIN FORECAST CONCERN REMAIN THE POTENTIAL FOR IFR/LIFR CONDITIONS OVERNIGHT...AND THEN THE TIMING OF TSRA MONDAY AFTERNOON. FOR THE REMAINDER OF THE OVERNIGHT HOURS...THE LOWEST CONDITIONS CONTINUE TO HUG THE COAST VFR CONDITIONS AT THE TERMINAL...OTHER THAN GYY WHICH IS ONLY AT 3SM BR. THERE IS STILL CONCERN THAT CONDITIONS WILL DETERIORATE OVERNIGHT...BUT WITH AN AREA OF SHRA MOVING TOWARD NERN IL THE LOWER LEVELS MAY REMAIN AGITATED ENOUGH TO MAINTAIN THE VFR CONDITIONS. HOWEVER...WITH LIGHT AND VARIABLE WINDS AND AMPLE LOW LEVEL MOISTURE...THERE WILL STILL BE OPPORTUNITY FOR CIGS OR VIS TO DROP RAPIDLY DURG THE PRE-DAWN HOURS WITH LOW STRATUS AND FOG OOZING INLAND FROM THE LAKEFRONT. GIVEN THE UNCERTAINTY OF THIS EVEN AT THIS SHORT DURATION...WILL MAINTAIN THE TEMPO GROUP FOR IFR CONDITIONS BUT DELAY THE POSSIBLE ONSET. THE PCPN FORECAST HAS EVEN GREATER UNCERTAINTY. THE ENVIRONMENT OVER NRN IL/IN REMAINS VERY MOIST AND SHOULD BECOME AT LEAST WEAKLY UNSTABLE THROUGH THE DAY TOMORROW. A MODERATE SHORTWAVE ALOFT HAS BEEN CONSISTENTLY FORECAST BY THE MODELS TO CROSS THE REGION TOMORROW AFTERNOON...AND WILL BE ACCOMPANIED BY A WEAK COLD FRONT. FRONTAL FORCING WILL BE LOW AS THERE WILL BE ONLY A MINOR AIRMASS CHANGE WITH THE FRONTAL PASSAGE AND A WINDSHIFT FROM LIGHT SOUTHERLY WINDS TO LIGHT NWLY WINDS. THERE MAY BE A FEW GUSTS TO ARND 15KT IN THE WEAK WARM ADVECTION AHEAD OF THE FRONT...BUT WINDS SHOULD BE LESS THAN 10KT BEHIND THE FRONT. HAVE TRIED TO NARROW DOWN THE MOST LIKELY PERIOD FOR TSRA TO IMPACT THE TERMINALS AND ADJUSTED THE PROB30 GROUP TO 19-22Z AT RFD AND 20-23Z AT THE CHICAGO METRO TERMINALS. THIS SHOULD COINCIDE WITH THE PASSAGE OF THE SHORTWAVE ALOFT AND THE WEAK COLD FRONT AT THE SURFACE. THE REMAINDER OF THE PERIOD SHOULD THEN BE DRY WITH NWLY WINDS ARND 10KT AND VFR CIGS/VIS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 09Z... * MEDIUM IN CIGS/VIS TRENDS FOR THE REST OF THE NIGHT. * HIGH IN SCT SHRA OVERNIGHT...THOUGH IMPACT WILL BE MINIMAL. * MEDIUM-HIGH IN WIND TRENDS. * LOW TO MEDIUM IN TSRA TIMING AND COVERAGE MONDAY AFTERNOON. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...SLIGHT CHANCE FOR TSRA. OTHERWISE VFR. WEDNESDAY...SLIGHT CHANCE FOR TSRA. OTHERWISE VFR. NORTHEAST WINDS. THURSDAY...CHANCE FOR TSRA. OTHERWISE VFR. EASTERLY WINDS. FRIDAY...CHANCE FOR TSRA. OTHERWISE VFR. SOUTHEAST WINDS POSSIBLY BECOMING EAST. SATURDAY...CHANCE TSRA. OTHERWISE VFR. RC && .MARINE... 315 AM CDT BROAD HIGH PRESSURE EXTENDS FROM THE GREAT LAKES REGION ACROSS MUCH OF THE EAST COAST. THE RESULTANT LIGHT AND VARIABLE WINDS COMBINED WITH RESIDUAL HIGH DEWPOINT AIR OVER THE STILL VERY COLD LAKE WATERS HAS KEPT DENSE FOG IN PLACE. THE DENSE FOG WILL CONTINUE WHILE THE HIGH PRESSURE IS SLOWLY ERODED BY A TROUGH OF WEAK LOW PRESSURE AS IT MOVES ACROSS THE MISSISSIPPI VALLEY MONDAY MORNING. THE TROUGH AND AN ASSOCIATED WEAK COLD FRONT WILL MOVE ACROSS THE LAKE LATE MONDAY NIGHT TURNING WINDS FROM LIGHT AND VARIABLE TO WESTERLY AND NORTHWESTERLY...WHICH WILL BEGIN TO SCOUR OUT THE FOG FROM THE LAKE. A SECONDARY COLD FRONT WILL DROP DOWN THE LAKE TUESDAY TURNING WINDS NORTHERLY BRINGING AN END TO ANY RESIDUAL FOG AS DRIER AIR FILTERS OVER THE LAKE. HIGH PRESSURE WILL BUILD ACROSS THE UPPER LAKES WEDNESDAY AND THURSDAY KEEPING CONDITIONS OVER THE LAKE RELATIVELY QUIET...BUT BY THE END OF THE WEEK...STRENGTHENING SOUTHERLY WINDS OF 15 TO 25 KT WILL DEVELOP OVER THE LAKE AS THE HIGH MOVES OFF TO THE EAST AND ANOTHER TROUGH APPROACHES FROM THE WEST. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ006-ILZ014 UNTIL 9 AM MONDAY. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
323 AM CDT MON JUN 23 2014 .DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * POTENTIAL FOR IFR/LIFR CIGS AND/OR VSBY IN BR/FG/STRATUS OVERNIGHT. * SHRA/TSRA POTENTIAL TONIGHT AND TOMORROW. KREIN //DISCUSSION...UPDATED 06Z... MAIN FORECAST CONCERN REMAIN THE POTENTIAL FOR IFR/LIFR CONDITIONS OVERNIGHT...AND THEN THE TIMING OF TSRA MONDAY AFTERNOON. FOR THE REMAINDER OF THE OVERNIGHT HOURS...THE LOWEST CONDITIONS CONTINUE TO HUG THE COAST VFR CONDITIONS AT THE TERMINAL...OTHER THAN GYY WHICH IS ONLY AT 3SM BR. THERE IS STILL CONCERN THAT CONDITIONS WILL DETERIORATE OVERNIGHT...BUT WITH AN AREA OF SHRA MOVING TOWARD NERN IL THE LOWER LEVELS MAY REMAIN AGITATED ENOUGH TO MAINTAIN THE VFR CONDITIONS. HOWEVER...WITH LIGHT AND VARIABLE WINDS AND AMPLE LOW LEVEL MOISTURE...THERE WILL STILL BE OPPORTUNITY FOR CIGS OR VIS TO DROP RAPIDLY DURG THE PRE-DAWN HOURS WITH LOW STRATUS AND FOG OOZING INLAND FROM THE LAKEFRONT. GIVEN THE UNCERTAINTY OF THIS EVEN AT THIS SHORT DURATION...WILL MAINTAIN THE TEMPO GROUP FOR IFR CONDITIONS BUT DELAY THE POSSIBLE ONSET. THE PCPN FORECAST HAS EVEN GREATER UNCERTAINTY. THE ENVIRONMENT OVER NRN IL/IN REMAINS VERY MOIST AND SHOULD BECOME AT LEAST WEAKLY UNSTABLE THROUGH THE DAY TOMORROW. A MODERATE SHORTWAVE ALOFT HAS BEEN CONSISTENTLY FORECAST BY THE MODELS TO CROSS THE REGION TOMORROW AFTERNOON...AND WILL BE ACCOMPANIED BY A WEAK COLD FRONT. FRONTAL FORCING WILL BE LOW AS THERE WILL BE ONLY A MINOR AIRMASS CHANGE WITH THE FRONTAL PASSAGE AND A WINDSHIFT FROM LIGHT SOUTHERLY WINDS TO LIGHT NWLY WINDS. THERE MAY BE A FEW GUSTS TO ARND 15KT IN THE WEAK WARM ADVECTION AHEAD OF THE FRONT...BUT WINDS SHOULD BE LESS THAN 10KT BEHIND THE FRONT. HAVE TRIED TO NARROW DOWN THE MOST LIKELY PERIOD FOR TSRA TO IMPACT THE TERMINALS AND ADJUSTED THE PROB30 GROUP TO 19-22Z AT RFD AND 20-23Z AT THE CHICAGO METRO TERMINALS. THIS SHOULD COINCIDE WITH THE PASSAGE OF THE SHORTWAVE ALOFT AND THE WEAK COLD FRONT AT THE SURFACE. THE REMAINDER OF THE PERIOD SHOULD THEN BE DRY WITH NWLY WINDS ARND 10KT AND VFR CIGS/VIS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 06Z... * LOW IN IFR/LIFR CIGS AND MVFR/IFR VIS FOR THE REST OF THE NIGHT. * MEDIUM-HIGH IN SOME SCT OVERNIGHT...THOUGH IMPACT WILL BE MINIMAL. * MEDIUM-HIGH IN WIND TRENDS. * LOW TO MEDIUM IN TSRA TIMING AND COVERAGE MONDAY AFTERNOON. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...SLIGHT CHANCE FOR TSRA. OTHERWISE VFR. WEDNESDAY...SLIGHT CHANCE FOR TSRA. OTHERWISE VFR. NORTHEAST WINDS. THURSDAY...CHANCE FOR TSRA. OTHERWISE VFR. EASTERLY WINDS. FRIDAY...CHANCE FOR TSRA. OTHERWISE VFR. SOUTHEAST WINDS POSSIBLY BECOMING EAST. SATURDAY...CHANCE TSRA. OTHERWISE VFR. RC && .MARINE... 315 AM CDT BROAD HIGH PRESSURE EXTENDS FROM THE GREAT LAKES REGION ACROSS MUCH OF THE EAST COAST. THE RESULTANT LIGHT AND VARIABLE WINDS COMBINED WITH RESIDUAL HIGH DEWPOINT AIR OVER THE STILL VERY COLD LAKE WATERS HAS KEPT DENSE FOG IN PLACE. THE DENSE FOG WILL CONTINUE WHILE THE HIGH PRESSURE IS SLOWLY ERODED BY A TROUGH OF WEAK LOW PRESSURE AS IT MOVES ACROSS THE MISSISSIPPI VALLEY MONDAY MORNING. THE TROUGH AND AN ASSOCIATED WEAK COLD FRONT WILL MOVE ACROSS THE LAKE LATE MONDAY NIGHT TURNING WINDS FROM LIGHT AND VARIABLE TO WESTERLY AND NORTHWESTERLY...WHICH WILL BEGIN TO SCOUR OUT THE FOG FROM THE LAKE. A SECONDARY COLD FRONT WILL DROP DOWN THE LAKE TUESDAY TURNING WINDS NORTHERLY BRINGING AN END TO ANY RESIDUAL FOG AS DRIER AIR FILTERS OVER THE LAKE. HIGH PRESSURE WILL BUILD ACROSS THE UPPER LAKES WEDNESDAY AND THURSDAY KEEPING CONDITIONS OVER THE LAKE RELATIVELY QUIET...BUT BY THE END OF THE WEEK...STRENGTHENING SOUTHERLY WINDS OF 15 TO 25 KT WILL DEVELOP OVER THE LAKE AS THE HIGH MOVES OFF TO THE EAST AND ANOTHER TROUGH APPROACHES FROM THE WEST. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ006-ILZ014 UNTIL 9 AM MONDAY. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
308 AM CDT MON JUN 23 2014 .DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * POTENTIAL FOR IFR/LIFR CIGS AND/OR VSBY IN BR/FG/STRATUS OVERNIGHT. * SHRA/TSRA POTENTIAL TONIGHT AND TOMORROW. KREIN //DISCUSSION...UPDATED 06Z... MAIN FORECAST CONCERN REMAIN THE POTENTIAL FOR IFR/LIFR CONDITIONS OVERNIGHT...AND THEN THE TIMING OF TSRA MONDAY AFTERNOON. FOR THE REMAINDER OF THE OVERNIGHT HOURS...THE LOWEST CONDITIONS CONTINUE TO HUG THE COAST VFR CONDITIONS AT THE TERMINAL...OTHER THAN GYY WHICH IS ONLY AT 3SM BR. THERE IS STILL CONCERN THAT CONDITIONS WILL DETERIORATE OVERNIGHT...BUT WITH AN AREA OF SHRA MOVING TOWARD NERN IL THE LOWER LEVELS MAY REMAIN AGITATED ENOUGH TO MAINTAIN THE VFR CONDITIONS. HOWEVER...WITH LIGHT AND VARIABLE WINDS AND AMPLE LOW LEVEL MOISTURE...THERE WILL STILL BE OPPORTUNITY FOR CIGS OR VIS TO DROP RAPIDLY DURG THE PRE-DAWN HOURS WITH LOW STRATUS AND FOG OOZING INLAND FROM THE LAKEFRONT. GIVEN THE UNCERTAINTY OF THIS EVEN AT THIS SHORT DURATION...WILL MAINTAIN THE TEMPO GROUP FOR IFR CONDITIONS BUT DELAY THE POSSIBLE ONSET. THE PCPN FORECAST HAS EVEN GREATER UNCERTAINTY. THE ENVIRONMENT OVER NRN IL/IN REMAINS VERY MOIST AND SHOULD BECOME AT LEAST WEAKLY UNSTABLE THROUGH THE DAY TOMORROW. A MODERATE SHORTWAVE ALOFT HAS BEEN CONSISTENTLY FORECAST BY THE MODELS TO CROSS THE REGION TOMORROW AFTERNOON...AND WILL BE ACCOMPANIED BY A WEAK COLD FRONT. FRONTAL FORCING WILL BE LOW AS THERE WILL BE ONLY A MINOR AIRMASS CHANGE WITH THE FRONTAL PASSAGE AND A WINDSHIFT FROM LIGHT SOUTHERLY WINDS TO LIGHT NWLY WINDS. THERE MAY BE A FEW GUSTS TO ARND 15KT IN THE WEAK WARM ADVECTION AHEAD OF THE FRONT...BUT WINDS SHOULD BE LESS THAN 10KT BEHIND THE FRONT. HAVE TRIED TO NARROW DOWN THE MOST LIKELY PERIOD FOR TSRA TO IMPACT THE TERMINALS AND ADJUSTED THE PROB30 GROUP TO 19-22Z AT RFD AND 20-23Z AT THE CHICAGO METRO TERMINALS. THIS SHOULD COINCIDE WITH THE PASSAGE OF THE SHORTWAVE ALOFT AND THE WEAK COLD FRONT AT THE SURFACE. THE REMAINDER OF THE PERIOD SHOULD THEN BE DRY WITH NWLY WINDS ARND 10KT AND VFR CIGS/VIS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 06Z... * LOW IN IFR/LIFR CIGS AND MVFR/IFR VIS FOR THE REST OF THE NIGHT. * MEDIUM-HIGH IN SOME SCT OVERNIGHT...THOUGH IMPACT WILL BE MINIMAL. * MEDIUM-HIGH IN WIND TRENDS. * LOW TO MEDIUM IN TSRA TIMING AND COVERAGE MONDAY AFTERNOON. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...SLIGHT CHANCE FOR TSRA. OTHERWISE VFR. WEDNESDAY...SLIGHT CHANCE FOR TSRA. OTHERWISE VFR. NORTHEAST WINDS. THURSDAY...CHANCE FOR TSRA. OTHERWISE VFR. EASTERLY WINDS. FRIDAY...CHANCE FOR TSRA. OTHERWISE VFR. SOUTHEAST WINDS POSSIBLY BECOMING EAST. SATURDAY...CHANCE TSRA. OTHERWISE VFR. RC && .MARINE... 303 PM CDT A MESO HIGH PRESSURE AREA OVER CENTRAL LAKE MICHIGAN INDUCED BY THE COOL WATERS OF THE LAKE ITSELF WILL REMAIN IN PLACE THIS EVENING ALONG WITH AN ABUNDANTLY MOIST AIRMASS AND THE ACCOMPANYING AREAS OF DENSE FOG. THIS FLAT PRESSURE PATTERN WILL GRADUALLY BE REPLACED WITH INCREASING SOUTHERLY FLOW AS LOW PRESSURE OVER THE CENTRAL PLAINS MOVES EAST TO TO NORTHEAST IOWA BY DAYBREAK MONDAY. WINDS WILL TURN MORE EAST ACROSS NORTHERN LAKE MICHIGAN NORTH OF A WARM FRONT ASSOCIATED WITH THE LOW MOVING SLOWLY NORTH. THIS LOW WILL THEN MOVE ACROSS WISCONSIN TO THE STRAITS OF MACKINAC BY DAYBREAK TUESDAY. A COLD FRONT ASSOCIATED WITH THIS LOW WILL SWEEP EAST ACROSS THE LAKE LATE MONDAY NIGHT... TURNING WINDS NORTHWEST. THIS WILL FINALLY SWEEP THE DENSE FOG OUT OF THE MARINE AREA. A SECONDARY COLD FRONT WILL THEN MOVE ACROSS THE LAKE TUESDAY NIGHT. HIGH PRESSURE WILL BUILD ACROSS THE UPPER GREAT LAKES WEDNESDAY AND THURSDAY. SOUTH FLOW WILL INCREASE AGAIN FRIDAY AS THIS HIGH MOVES EAST. ED F && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ006-ILZ014 UNTIL 9 AM MONDAY. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1136 PM MDT SUN JUN 22 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 1230 PM MDT SUN JUN 22 2014 THUNDERSTORM ACTIVITY EXPECTED TO RAMP UP QUICKLY AFTER 3 PM MDT (4 PM CDT) AS A WEATHER DISTURBANCE IGNITES A FEW STORMS IN FAR EASTERN COLORADO. AS THE DISTURBANCE MOVES EAST A LINE OF STRONG TO SEVERE THUNDERSTORMS IS EXPECTED PRODUCING LARGE HAIL...DAMAGING WINDS AND LOCALLY HEAVY RAINFALL. THE HRRR HAS BEEN SLOWLY INCREASING THE WIND GUST POTENTIAL WITH THE LINE AND WE COULD EXPERIENCE ANOTHER EPISODE OF 70+ MPH GUSTS. LOWS TONIGHT IN THE MID 50S WEST...MID 60S EAST. ON MONDAY MAY SEE SHOWERS AND THUNDERSTORMS IN THE LATE AFTERNOON HOURS...PRIMARILY ACROSS FAR EASTERN COLORADO. OTHERWISE EXPECT SOME CLOUDINESS WITH HIGHS IN THE MID 70S TO LOW 80S. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 1242 PM MDT SUN JUN 22 2014 A FEW STORMS IN SOUTHEAST COLORADO MONDAY EVENING MAY SNEAK INTO SOUTHWESTERN PARTS OF THE AREA...BUT BETTER CHANCES WILL BE AFTER MIDNIGHT AS LLJ STRENGTHENS AND SHORTWAVE TROUGH COMES OUT OF THE NORTHERN ROCKIES. STORMS MAY BE SLIGHTLY ELEVATED OVERNIGHT...WITH PARCELS ORIGINATING AROUND 800MB HAVING UP TO 1000 J/KG OF ELEVATED CAPE AND LITTLE TO NO CIN. LARGE HAIL WILL BE POSSIBLE OVERNIGHT WITH THESE STORMS. SOME OF THIS ACTIVITY WILL LINGER INTO TUESDAY MORNING...PARTICULARLY IN SOUTHWEST NEBRASKA...BEFORE AFTERNOON CONVECTION GETS GOING IN NORTHEAST COLORADO WITH THE NEXT SHORTWAVE. MODERATE INSTABILITY COMBINED WITH DEEP LAYER SHEAR OF 30-40KTS SUGGEST ANOTHER ROUND OF SEVERE STORMS AS THEY SLIDE ACROSS THE AREA TUESDAY EVENING. SOUTHEASTERLY SURFACE WINDS CONTINUE ON WEDNESDAY WITH A CORRIDOR OF VERY UNSTABLE CONDITIONS FORECAST BY THE AFTERNOON IN THE WESTERN HALF OF THE FORECAST AREA. DEEP LAYER SHEAR HOWEVER IS SOMEWHAT WEAKER AT AROUND 30KTS...BUT SHOULD BE ADEQUATE FOR SEVERE STORMS AS NEXT SHORTWAVE COMES OUT OF NORTHERN COLORADO IN THE AFTERNOON/EVENING. A SUBTLE PATTERN CHANGE OCCURS IN THE LAST HALF OF THE LONG TERM PERIOD WITH LONGWAVE TROUGH SETTLING INTO THE NORTHERN ROCKIES. THE UPPER FLOW OVER THE CENTRAL PLAINS WILL BECOME SOUTHWEST. SHORTWAVE TROUGHS ROTATING AROUND THE ROCKIES TROUGH OR EVEN THE RIDGE OVER THE CENTRAL GULF WILL PROVIDE ENOUGH LIFT TO CONTINUE THE MENTION OF DAILY THUNDERSTORM CHANCES. TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE LONG TERM. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1136 PM MDT SUN JUN 22 2014 VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD AT BOTH KGLD AND KMCK. EARLY IN THE TAF PERIOD SHOWERS WITH EMBEDDED THUNDERSTORMS WILL CONTINUE TO MOVE EAST ACROSS SW NEBRASKA...WITH A FEW SHOWERS POSSIBLY MAKING IT AS FAR SOUTH AS KGLD. BY 09Z THIS ACTIVITY SHOULD BE OUTSIDE THE VICINITY OF BOTH TERMINALS. WINDS ARE GENERALLY GOING TO BE LESS THAT 12KT THROUGH MOST OF THE TAF PERIOD...WITH SLIGHTLY STRONGER WINDS IN THE 10-15KT RANGE MONDAY WHERE THE PRESSURE GRADIENT WILL BE A LITTLE TIGHTER DUE TO PROXIMITY OF SURFACE TROUGH. ADDITIONAL THUNDERSTORM ACTIVITY IS EXPECTED MONDAY AND MONDAY NIGHT. THERE IS STILL UNCERTAINTY REGARDING TIMING AND COVERAGE AT THIS POINT...SO I LEFT MENTION OF OF THE TAFS DURING THIS UPDATE AFTER THE CURRENT ACTIVITY ENDS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...99 LONG TERM...024 AVIATION...DR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
422 AM EDT MON JUN 23 2014 .SYNOPSIS... THE WEATHER WILL BE A LITTLE WARMER AND MORE HUMID TODAY WITH AN ISOLATED STORM. THE BEST CHANCE FOR WET WEATHER WILL BE TUESDAY INTO WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... DRY WEATHER IS EXPECTED FOR THE START OF THE DAY...ALTHOUGH SOME HIGH CLOUDS WILL REMAIN OVER EASTERN OHIO. IN ADDITION...MANY LOCATIONS WILL HAVE SOME FOG. ANY LOCATION COULD SEE AN ISOLATED THUNDERSTORM TODAY...ALTHOUGH THE FOCUS WILL LIKELY REMAIN OVER THE LAUREL HIGHLANDS. A FEATURE NOT PREVIOUSLY SHOWN ON MODEL RUNS IS A SHORTWAVE THAT COULD DEVELOP OVER WESTERN OHIO LATE THIS AFTERNOON AND TRACK OVER NORTHWESTERN PENNSYLVANIA BY MIDNIGHT. WHILE THE NAM MOST CLEARLY DEPICTS THIS SHORTWAVE...THE END OF THE RAP MODEL RUN HINTS AT THIS DEVELOPMENT...AND VARIOUS HIGH RESOLUTION NMM RUNS ALSO DEVELOP THIS PRECIPITATION DURING THE EVENING HOURS. HAVE RAISED POPS SLIGHTLY DURING THE EVENING HOURS...DECREASING POPS AGAIN AFTER MIDNIGHT. WITH UPPER RIDGE BUILDING IN...TEMPS WILL BE ABOUT FIVE DEGREES WARMER TODAY THAN YESTERDAY. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... UNFORTUNATELY...THE 00Z GFS SUFFERS FROM CONVECTIVE FEEDBACK...SPINNING UP A SURFACE LOW ALONG THE APPROACHING COLD FRONT AND SHOWING UNREALISTIC PRECIPITATION AND VORTICITY MAXIMA. AS A RESULT...THE 00Z GFS WAS NOT USED THROUGH THIS PORTION OF THE FORECAST. PRIMARY CHANGE DURING THIS PORTION OF THE FORECAST WAS TO SLOW DOWN THE TIMING OF THE COLD FRONT. COMPARED TO MODEL RUNS FROM 24 HOURS AGO...FRONT APPEARS TO BE ABOUT 6 HOURS SLOWER IN ITS ARRIVAL AND PASSAGE WITH LATEST MODEL RUNS. THIS MEANS MANY LOCATIONS COULD REMAIN DRY TUESDAY MORNING...ALTHOUGH RAIN IS STILL EXPECTED EVERYWHERE BY TUESDAY EVENING. STRONG SHEAR VALUES REMAIN CONFINED TO THE LAKE ERIE SHORELINE...WHICH SHOULD KEEP THE THREAT FOR SEVERE STORMS FARTHER TO THE NORTH..BUT SOME STRONGER STORMS REMAIN POSSIBLE WITH MODEST INSTABILITY. BIGGER CONCERN COULD POSSIBLY BE HEAVY RAINFALL TUESDAY AFTERNOON AND NIGHT WITH PRECIPITABLE WATER VALUES RANGING FROM 1.5 INCHES ACROSS WV/MD RIDGES TO NEARLY 2 INCHES IN EASTERN OHIO AND NORTHWESTERN PENNSYLVANIA. THESE PWAT VALUES ARE NEAR THE 99TH PERCENTILE FOR JUNE...AND IF SHOWERS/STORM TRAIN ALONG THE FRONT...SOME LOCATIONS COULD SEE SEVERAL ROUNDS OF MODERATE TO HEAVY RAIN. HOWEVER...THE RELATIVELY DRY WEEKEND THAT JUST OCCURRED SHOULD HELP TO ALLEVIATE CONCERNS. MOST RAINFALL SHOULD FALL IN ADVANCE OF THE COLD FRONT...WHICH SHOULD ACTUALLY PASS OVER THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. RAIN SHOULD HANG ON FOR A WHILE INTO WEDNESDAY AFTERNOON ACROSS THE WV/MD RIDGES...BUT THINK THAT PRECIP CHANCES WILL DROP QUITE A BIT WEDNESDAY AFTERNOON...WITH NEARLY ALL LOCATIONS DRY BY WEDNESDAY NIGHT. A COUPLE OF WARM NIGHTS CAN BE EXPECTED DUE TO THE EXTENSIVE CLOUD COVER. DAYTIME HIGHS WILL BE SLIGHTLY ABOVE NORMAL TUESDAY AND SLIGHTLY BELOW NORMAL WEDNESDAY BEHIND THE COLD FRONT. && .LONG TERM /THURSDAY THROUGH SUNDAY/... KEEPING THURSDAY DRY WITH HIGH PRESSURE IN PLACE AND RELATIVELY LOW MOISTURE. FRONTAL BOUNDARY WILL RETURN NORTHWARD AS A WARM FRONT THURSDAY NIGHT/FRIDAY...BRINGING HIGHER PRECIPITABLE WATER VALUES BACK NORTHWARD. FROM HERE ON OUT...EXPECTING A DAILY CHANCE OF SHOWERS/THUNDERSTORMS AS H500 HEIGHTS SLOWLY RISE AND WE STAY IN A TYPICALLY WARM AND MOIST SUMMERTIME AIRMASS. DECIDED TO KEY ON DIURNAL POPS FOR NOW...EVEN THOUGH RIPPLES IN THE WESTERLIES MAY PROVIDE ENHANCED CHANCES. TEMPERATURES WILL FLOAT TO A BIT ABOVE SEASONAL LEVELS WITH TIME. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS EARLY TONIGHT FOLLOWED BY MVFR FOG WITH ONLY KMGW EXPECTED TO REACH IFR. FOG WILL BURN OFF QUICKLY OVER THE COURSE OF THE MORNING. THE MAJORITY OF THE AFTERNOON WILL BE QUIET...BUT BY LATE AFTERNOON/ EVENING SHOWERS AND THUNDERSTORMS WILL EXPAND IN COVERAGE AS THE CAP ALOFT ERODES AND ALLOWS FOR DEEPER CONVECTIVE DEVELOPMENT. .OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/... THE BEST CHANCE FOR RESTRICTIONS WILL BE TUESDAY INTO WEDNESDAY WITH FRONTAL BOUNDARY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
346 AM EDT MON JUN 23 2014 .SYNOPSIS... THE WEATHER WILL BE A LITTLE WARMER AND MORE HUMID TODAY WITH AN ISOLATED STORM. THE BEST CHANCE FOR WET WEATHER WILL BE TUESDAY INTO WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... DRY WEATHER IS EXPECTED FOR THE START OF THE DAY...ALTHOUGH SOME HIGH CLOUDS WILL REMAIN OVER EASTERN OHIO. IN ADDITION...MANY LOCATIONS WILL HAVE SOME FOG. ANY LOCATION COULD SEE AN ISOLATED THUNDERSTORM TODAY...ALTHOUGH THE FOCUS WILL LIKELY REMAIN OVER THE LAUREL HIGHLANDS. A FEATURE NOT PREVIOUSLY SHOWN ON MODEL RUNS IS A SHORTWAVE THAT COULD DEVELOP OVER WESTERN OHIO LATE THIS AFTERNOON AND TRACK OVER NORTHWESTERN PENNSYLVANIA BY MIDNIGHT. WHILE THE NAM MOST CLEARLY DEPICTS THIS SHORTWAVE...THE END OF THE RAP MODEL RUN HINTS AT THIS DEVELOPMENT...AND VARIOUS HIGH RESOLUTION NMM RUNS ALSO DEVELOP THIS PRECIPITATION DURING THE EVENING HOURS. HAVE RAISED POPS SLIGHTLY DURING THE EVENING HOURS...DECREASING POPS AGAIN AFTER MIDNIGHT. WITH UPPER RIDGE BUILDING IN...TEMPS WILL BE ABOUT FIVE DEGREES WARMER TODAY THAN YESTERDAY. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... UNFORTUNATELY...THE 00Z GFS SUFFERS FROM CONVECTIVE FEEDBACK...SPINNING UP A SURFACE LOW ALONG THE APPROACHING COLD FRONT AND SHOWING UNREALISTIC PRECIPITATION AND VORTICITY MAXIMA. AS A RESULT...THE 00Z GFS WAS NOT USED THROUGH THIS PORTION OF THE FORECAST. PRIMARY CHANGE DURING THIS PORTION OF THE FORECAST WAS TO SLOW DOWN THE TIMING OF THE COLD FRONT. COMPARED TO MODEL RUNS FROM 24 HOURS AGO...FRONT APPEARS TO BE ABOUT 6 HOURS SLOWER IN ITS ARRIVAL AND PASSAGE WITH LATEST MODEL RUNS. THIS MEANS MANY LOCATIONS COULD REMAIN DRY TUESDAY MORNING...ALTHOUGH RAIN IS STILL EXPECTED EVERYWHERE BY TUESDAY EVENING. STRONG SHEAR VALUES REMAIN CONFINED TO THE LAKE ERIE SHORELINE...WHICH SHOULD KEEP THE THREAT FOR SEVERE STORMS FARTHER TO THE NORTH..BUT SOME STRONGER STORMS REMAIN POSSIBLE WITH MODEST INSTABILITY. BIGGER CONCERN COULD POSSIBLY BE HEAVY RAINFALL TUESDAY AFTERNOON AND NIGHT WITH PRECIPITABLE WATER VALUES RANGING FROM 1.5 INCHES ACROSS WV/MD RIDGES TO NEARLY 2 INCHES IN EASTERN OHIO AND NORTHWESTERN PENNSYLVANIA. THESE PWAT VALUES ARE NEAR THE 99TH PERCENTILE FOR JUNE...AND IF SHOWERS/STORM TRAIN ALONG THE FRONT...SOME LOCATIONS COULD SEE SEVERAL ROUNDS OF MODERATE TO HEAVY RAIN. HOWEVER...THE RELATIVELY DRY WEEKEND THAT JUST OCCURRED SHOULD HELP TO ALLEVIATE CONCERNS. MOST RAINFALL SHOULD FALL IN ADVANCE OF THE COLD FRONT...WHICH SHOULD ACTUALLY PASS OVER THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. RAIN SHOULD HANG ON FOR A WHILE INTO WEDNESDAY AFTERNOON ACROSS THE WV/MD RIDGES...BUT THINK THAT PRECIP CHANCES WILL DROP QUITE A BIT WEDNESDAY AFTERNOON...WITH NEARLY ALL LOCATIONS DRY BY WEDNESDAY NIGHT. A COUPLE OF WARM NIGHTS CAN BE EXPECTED DUE TO THE EXTENSIVE CLOUD COVER. DAYTIME HIGHS WILL BE SLIGHTLY ABOVE NORMAL TUESDAY AND SLIGHTLY BELOW NORMAL WEDNESDAY BEHIND THE COLD FRONT. && .LONG TERM /THURSDAY THROUGH SUNDAY/... DRY CONDITIONS AND SEASONAL TEMPERATURES CAN BE EXPECTED ON THURSDAY AS HIGH PRESSURE BUILDS IN ACROSS THE FORECAST AREA. ON FRIDAY FLOW ALOFT WILL BECOME SOUTHWESTERLY...INCREASING THE CHANCE FOR SHOWERS AND THUNDERSTORMS AS DEWPOINTS CLIMB BACK UP IN THE THE MID 60S AND AS WARM FRONT LIFTS NORTH ACROSS THE FORECAST AREA. THIS WILL CARRY INTO SATURDAY AS THE AFOREMENTIONED FRONTAL BOUNDARY SITS OVER OR JUST NORTH OF THE FORECAST AREA. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS EARLY TONIGHT FOLLOWED BY MVFR FOG WITH ONLY KMGW EXPECTED TO REACH IFR. FOG WILL BURN OFF QUICKLY OVER THE COURSE OF THE MORNING. THE MAJORITY OF THE AFTERNOON WILL BE QUIET...BUT BY LATE AFTERNOON/ EVENING SHOWERS AND THUNDERSTORMS WILL EXPAND IN COVERAGE AS THE CAP ALOFT ERODES AND ALLOWS FOR DEEPER CONVECTIVE DEVELOPMENT. .OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/... THE BEST CHANCE FOR RESTRICTIONS WILL BE TUESDAY INTO WEDNESDAY WITH FRONTAL BOUNDARY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
523 AM EDT MON JUN 23 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 522 AM EDT MON JUN 23 2014 WV IMAGERY AND RUC ANALYSIS INDICATED WSW FLOW INTO THE NRN LAKES BETWEEN A MID/UPPER LEVEL TROUGH FROM MANITOBA INTO THE NRN PLAINS AND A RIDGE FROM THE OHIO VALLEY INTO QUEBEC. AT THE SFC...A WEAK TROUGH EXTENDED FROM NE MN INTO WRN WI. A MORE PROMINENT COLD FRONT STRETCHED FROM JAMES BAY TO NEAR WINNIPEG AHEAD OF HIGH PRESSURE OVER N CNTRL CANADA. FORCING FROM A WEAK SHRTWV IN NRN WI ALONG WITH AN AXIS OF HIGHER MOISTURE WITH PWAT VALUES TO 1.4 INCHES...WAS ENOUGH TO SUPPORT AN AREA OF SHOWERS OVER FROM SW UPPER MI INTO E CNTRL WI. TODAY...EXPECT THE SHRTWV AND AREA OF PCPN ONLY SLOWLY MOVE TO THE EAST THIS MORNING. WITH ONLY WEAK LARGE SCALE FORCING EXPECTED INTO THE AFTERNOON AND THE POTENTIAL FOR ANOTHER WEAK SHRTWV TO MOVE INTO THE AREA DURING INCREASED DAYTIME HEATING...THE FCST KEEPS MENTION OF JUST SCT SHRA WITH THE GREATEST COVERAGE EXPECTED OVER CNTRL UPPER MI. WITH TEMPS CLIMBING INTO THE MID 70S...THERE MAY BE ENOUGH INSTABILITY FOR SOME ISOLD/SCT TSRA AS MLCAPE VALUES CLIMB INTO THE 400-800 J/KG RANGE. TONIGHT...WITH THE LOSS OF DAYTIME HEATING...THE PCPN COVERAGE SHOULD DIMINISH. HOWEVER...INCREASED QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH MOVING INTO THE UPPER MS VALLEY WILL SUPPORT CONTINUED CHANCES FOR SCT SHOWERS AND A FEW TSRA. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 421 AM EDT MON JUN 23 2014 ON TUESDAY MORNING...THE MODELS ARE IN GOOD AGREEMENT IN SHOWING THE COLD FRONT MOVING OVER OR JUST SOUTH OF THE AREA. HOWEVER...THE 850MB TROUGH AXIS HANGS UP OVER LAKE SUPERIOR AS THERE IS LACK OF A SOUTHWARD PUSH DUE TO THE GENERAL ZONAL FLOW ALOFT. THIS WILL PROVIDE THE FOCUS FOR PRECIPITATION ON TUESDAY ESPECIALLY SINCE THE MODELS ARE IN EXCELLENT AGREEMENT IN SHOWING BROAD SYNOPTIC SUPPORT MOVING THRU AS THE 500MB TROUGH AXIS MOVES THROUGH. AS SUCH...THERE WILL LIKELY BE SCATTERED SHOWERS ACROSS THE ENTIRE FORECAST AREA THROUGH THE DAY DESPITE THE SURFACE FRONT BEING SOUTH OF THE REGION. THE NUMERICAL GUIDANCE ALSO SHOWS MUCAPE VALUES OF 500-1500 J/KG ACROSS THE REGION DURING THE DAY WITH MID LEVEL LAPSE RATES OF 6+ C/KM...ALLOWING FOR POSSIBLE THUNDERSTORM DEVELOPMENT. BEST CHANCES FOR THUNDER WOULD BE ACROSS THE SOUTHERN TIER WHERE SFC TEMPS WILL LIKELY BE IN THE LOWER-MID 70S AND IS WHERE THE BEST INSTABILITY WILL BE LOCATED. WILL NEED TO KEEP CHANCE POPS ACROSS THE EASTERN HALF OF THE FORECAST AREA DURING THE TUE EVENING HOURS AS WELL GIVEN REMAINING MID LEVEL FORCING AND REMAINING DAYTIME INSTABILITY. AT THIS TIME...WEDNESDAY IS EXPECTED TO REMAIN DRY AND COOL WITH THE 850MB TROUGH AND SFC FRONT REMAINING SOUTH OF THE AREA. STILL SOME WEAK TROUGHINESS AT 500MB AND AS SUCH WEAK MID LEVEL Q-VECTOR CONVERGENCE AND MOISTURE PERSISTS ACROSS THE AREA ALL DAY. HOWEVER...GIVEN LACK OF INSTABILITY AND VERY WEAK MID LEVEL LAPSE RATES COMBINED WITH ANTICYCLONIC LOW LEVELS WILL KEEP IT DRY FOR NOW. WOULD NOT BE SHOCKED TO SEE ISOLATED SHOWERS BUT CHANCES ARE NOT HIGH ENOUGH TO INCLUDE IN THE FORECAST AT TIME TIME. IN THE EXTENDED...ZONAL FLOW THROUGH THE PERIOD WILL MAKE TIMING OF PRECIPITATION SOMEWHAT DIFFICULT ESPECIALLY INTO THE WEEKEND. HOWEVER...THE LONGER RANGE MODELS ARE IN DECENT AGREEMENT ON THE BROAD SCALE FEATURES WHICH AT LEAST GIVES SOME BASIC CONFIDENCE ON WHEN THE BETTER CHANCES FOR RAIN WILL BE. ON THURSDAY...THE ECMWF AND GFS BOTH SHOW A COMPACT VORT MAX MOVING ACROSS THE AREA DURING THE DAY AS THE 850MB FRONT MOVES BACK NORTH. ALTHOUGH MOISTURE WILL BE VERY LIMITED...WILL INCLUDE CHANCE POPS FOR THE WESTERN HALF OF THE FORECAST AREA. BEHIND THIS VORT MAX...UPPER RIDGING BUILDS ACROSS THE AREA FOR FRIDAY WHICH SHOULD ALLOW FOR TEMPS TO RETURN TO NORMAL AS WELL AS DRY WEATHER. RETURN FLOW BEGINS IN EARNEST FOR THE WEEKEND WITH TEMPERATURES LIKELY TO RISE ABOVE NORMAL...AND PERHAPS A LITTLE MORE HUMIDITY AND SUMMER LIKE WEATHER. THIS WILL ALLOW FOR CHANCES OF SHOWERS AND STORMS EACH DAY...ALTHOUGH SUNDAY LOOKS LIKE THE BETTER CHANCE FOR SHOWERS AND STORMS GIVEN LOWERING HEIGHTS ACROSS THE AREA IN RESPONSE TO THE APPROACHING TROUGH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 124 AM EDT MON JUN 23 2014 SOME -SHRA MAY IMPACT IWD AND CMX TNGT AS A DISTURBANCE MOVES NEWD INTO THE UPR GREAT LKS. THESE SITES WL LIKELY SEE DVLPG MVFR CONDITIONS WITH NOCTURNAL COOLING...ESPECIALLY IF SOME HEAVIER RA FALLS. NOT OUT OF THE QUESTION THERE COULD BE IFR CONDITIONS ESPECIALLY AT CMX WHERE MOISTENING OF THE LK COOLED AIRMASS WOULD RESULT IN FOG/STRATUS...BUT RATHER DRY NATURE OF AIRMASS IN PLACE NEAR TAF ISSUANCE AND DIMINISHING -SHRA TO THE SW INDICATES THIS CHC IS NOT THAT HI. AT SAW...LO CLDS NEAR THE LK MI SHORE MAY ARRIVE LATER TNGT IN LLVL SLY FLOW. AS THE UPR DISTURBANCE EXITS TO THE NE ON MON AND DAYTIME HEATING TAKE HOLD...ANY FOG/LO CLDS SHOULD DSPT AND GIVE WAY TO VFR WX. BUT THE LO CLDS COULD BE RESILIENT AT CMX WITH LK MODIFIED AND PSBLY RA COOLED AIRMASS DOMINATING. MORE INSTABILITY SHRA AND PERHAPS A TS COULD IMPACT SAW MAINLY IN THE AFTN AND EARLY EVNG. BEST CHC FOR MORE LO CLDS/FOG TO DVLP WOULD BE AT CMX...WITH RELATIVELY COOL/MOIST MARINE LYR DOMINATING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 522 AM EDT MON JUN 23 2014 DENSE FOG WILL PERSIST OVER WESTERN LAKE SUPERIOR INTO THIS AFTERNOON. OTHERWISE...MAINLY LIGHT WINDS WILL PREVAIL INTO TONIGHT. AS A COLD FRONT MOVES THROUGH THE AREA ON TUESDAY...NORTHEAST WINDS WILL INCREASE TO 20 KNOTS WITH WAVES BUILDING TO AROUND 4 FEET. WINDS WILL DIMINISH TUE NIGHT INTO WED AS HIGH PRES BUILDS INTO THE REGION. MAINLY LIGHT WINDS AT OR BELOW 15 KNOTS ARE THEN EXPECTED THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR LSZ162-240>248-263>265. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MRD AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
259 AM CDT Mon Jun 23 2014 .SHORT TERM: (Through Wednesday) Issued at 258 AM CDT Mon Jun 23 2014 A decaying MCV was moving through northeast MO into west central IL early this morning. A 20-30kt southwesterly LLJ was also interacting with multiple outflow boundaries across MO/IL at times. These features should keep isolated to scattered convection percolating through the early morning hours across parts of the CWA. DCVA ahead of an approaching mid/upper vort max should provide sufficient lift within a moist air mass for widespread SHRA/TSRA today and tonight along a weak cold front with precip lingering into Tue across the southeastern portion of the CWA. Expect daytime high temperatures to be a bit cooler today due to widespread cloud cover and pcpn. Some models depict a surface low developing along the trailing edge of the surface cold front or effective boundary in OK which then lifts northeastward through southeastern MO. If this occurs, then schc-chc PoPs might be too low on Tue night into Wed across the southeastern CWA. Kanofsky .LONG TERM: (Wednesday through Sunday) Issued at 258 AM CDT Mon Jun 23 2014 The upper air pattern remains nearly quasizonal through the middle of the week with an occasional synoptic disturbance or remnant MCV to support SHRA/TSRA through the week. Initially weak upper ridging over MO/IL on Thu is forecast to amplify by the end of the week in response to troughing over the West Coast. Expect daytime highs to warm back into the upper 80s to around 90 degrees by the weekend due to southwesterly surface flow and rising heights. Kanofsky && .AVIATION: (For the 06z TAFs through 06z Monday Night) Issued at 1028 PM CDT Sun Jun 22 2014 Convection along outflow boundary will move through COU with weaker convection moving through UIN until 07Z or 08Z Monday. Some of this convection may make it into the St Louis metro area late tonight, but may leave the St Louis metro area tafs dry for now as the latest HRRR model dissipates most of the convection before it makes it into the St Louis metro area. Should be mainly just high level convective cloud debris outside of the shower/storm activity late tonight. Diurnal cumulus clouds will develop late Monday morning and afternoon with showers and thunderstorms expected mainly during the late morning and afternoon for COU, the afternoon for UIN, and the late afternoon and early evening for the St Louis metro area as a weak cold front approaches. Surface winds will be mainly swly on Monday. Specifics for KSTL: Mainly just mid-high level clouds late tonight with most of the convection remaining north and west of STL. Diurnal cumulus clouds will develop late Monday morning and afternoon with the best chance of showers and storms during the late afternoon and early evening hours. The surface wind will be mainly light and s-swly late tonight, then increasing to around 8-9 kts by Monday afternoon from a swly direction, and diminishing Monday night and veering around to a w-nwly direction after fropa by late Monday night. GKS && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1102 PM CDT Sun Jun 22 2014 .UPDATE: Issued at 937 PM CDT Sun Jun 22 2014 In the process of making some adjustment to PoPs based on latest short-term precip trends. It appears that main convection threat over the next few hours will be tied to outflow boundary dropping south across western MO. This should bring an uptick of PoPs into the likely category over mid MO over the next few hours, with this activity then gradually waning as outflow drops further south and ams becomes somewhat less unstable due to nocturnal cooling. This activity should at least partially cut into precip potential over northeast MO/west central IL due to the increase of stability of the ams in the wake of the outflow. However, in the 09-12z time frame, models are still indicating a weak WAA pattern which could regenerate some elevated convection during the predawn hours (similar to what occurred early this morning), and this should bring some low PoPs to se sections of the CWA. Forecast that reflects this thinking will be out shortly. Truett && .SHORT TERM: (Through Late Tonight) Issued at 350 PM CDT Sun Jun 22 2014 A nearly stationary front was laid out near the MS river this afternoon and is acting as the primary focus for TSRA development. Another source for TSRA development is a MCV located along the MO-IA border north of Kansas City that is headed east and has a tail of TSRA extending south to near the Kansas City area thanks to a surface outflow boundary. Otherwise, a typical partly cloudy summer day in most areas with temps pushing 90--unless you`ve seen rain, like Farmington sitting at 68. The quasi-stationary front is expected to weaken in identity tonight as well as push northeast as a warm front. The bottom line for this will be dissipation of the TSRA during the evening with loss of heating and weakening of moisture convergence. One thing that may prolong this, like last night, is if individual cells can merge together enough to form a more coherent structure. If that happens, storms and their intensity will likely last towards midnight. The MCV along the MO-IA border is expected to move into central IL by late this evening, with TSRA likely during that time over the northern CWA, around Quincy. Some breaks are expected late this evening and a part overnight. One final source for rain will be a shortwave TROF that will strengthen over the central Plains tonight and will extend its influence towards central MO by sunrise. This should lead to increasing PoPs very late tonight in central MO and perhaps back into northeast MO and west-central IL. Min temps are close to persistence/MOS, which has verified well the past few days. TES .LONG TERM: (Monday through Next Sunday) Issued at 350 PM CDT Sun Jun 22 2014 The current pattern we are in will continue relatively unaltered through late Thursday, with a flat west-east mid-level flow and periodic effects from upper level disturbances or MCVs. This will continue the unsettled wx and TSRA chances thru much of this period, only being limited when available moisture becomes a factor, or enhanced when a clear focus can be seen. Strong chances for SHRA/TSRA are still expected on Monday, especially afternoon, and Monday night with a more significant shortwave TROF that will pass into a convectively favorable atmosphere--and maintained likely PoPs as a result. Much of Tuesday and Wednesday look to be a couple of dry days for most areas, provided the 12z GFS is not correct with its much stronger and slower depiction of the shortwave and associated surface wave. Daytime max temps should be in the 80s these days. Rain chances could return for a widespread area on Thursday with some models depicting the return of rich and deep moisture and another upper level shortwave. A deep and amplified upper TROF is then expected to dig into the western CONUS for the end of the week, more consistently depicted by the EC. This is expected to result in temps returning closer to the low 90s for daytime maxes with reduced PoPs. TES && .AVIATION: (For the 06z TAFs through 06z Monday Night) Issued at 1028 PM CDT Sun Jun 22 2014 Convection along outflow boundary will move through COU with weaker convection moving through UIN until 07Z or 08Z Monday. Some of this convection may make it into the St Louis metro area late tonight, but may leave the St Louis metro area tafs dry for now as the latest HRRR model dissipates most of the convection before it makes it into the St Louis metro area. Should be mainly just high level convective cloud debris outside of the shower/storm activity late tonight. Diurnal cumulus clouds will develop late Monday morning and afternoon with showers and thunderstorms expected mainly during the late morning and afternoon for COU, the afternoon for UIN, and the late afternoon and early evening for the St Louis metro area as a weak cold front approaches. Surface winds will be mainly swly on Monday. Specifics for KSTL: Mainly just mid-high level clouds late tonight with most of the convection remaining north and west of STL. Diurnal cumulus clouds will develop late Monday morning and afternoon with the best chance of showers and storms during the late afternoon and early evening hours. The surface wind will be mainly light and s-swly late tonight, then increasing to around 8-9 kts by Monday afternoon from a swly direction, and diminishing Monday night and veering around to a w-nwly direction after fropa by late Monday night. GKS && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
319 AM CDT MON JUN 23 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 319 AM CDT MON JUN 23 2014 ANOTHER MCS SHOULD DROP THROUGH THE CNTL HIGH PLAINS THIS AFTN. THE FORECAST USES 50 PERCENT OF THE RAP MODEL AND 50 PERCENT OF THE OTHER MODELS. THE ONGOING MCS APPEARS TO BE TAKING ON A CYCLONIC ROTATION WITH THE WARM SECTOR ACROSS SCNTL NEB AND THE UPPER LEVEL COLD POOL ACROSS SWRN NEB ATTM. RADAR TRENDS SUGGEST THIS SYSTEM COULD ROTATE THROUGH SCNTL NEB THIS MORNING AND SHOWERS AND TSTMS ARE POPPING LEFT AND RIGHT BETWEEN KLBF AND KLXN. FOR TONIGHT...NEBULOUS POPS ARE IN THE FCST ACROSS THE SANDHILLS AND AREAS SOUTH. GIVEN THE INABILITY OF THE SYNOPTIC SCALE MODELS TO PREDICT NOCTURNAL RAIN EVENTS OF LATE...THE FCST IS FORCED TO MAINTAIN A SCATTERED POP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 319 AM CDT MON JUN 23 2014 12Z TUESDAY AND BEYOND. NEAR DAILY PRECIPITATION CHANCES TO HEADLINE THE EXTENDED DISCUSSION THROUGH AT LEAST SATURDAY AS THE ACTIVE PATTERN CONTINUES. A BRIEF PERIOD OF NORTHWEST FLOW ALOFT WILL DIRECT TWO SUBTLE DISTURBANCES ACROSS THE CENTRAL PLAINS TUESDAY INTO WEDNESDAY. THE FIRST OF WHICH SHOULD BE EAST OF THE CWA BY 12Z TUESDAY. THERE REMAINS GOOD CONSENSUS HOWEVER THAT THUNDER CHANCES REMAIN THROUGH MUCH THE DAY AS THE NEXT DISTURBANCE FOLLOWS. THE ATMOSPHERE WILL CHARACTERIZED AS MODERATELY UNSTABLE...WITH GENERALLY 25-40 KTS OF DEEP LAYER SHEAR. STRONG TO SEVERE STORMS ARE ANTICIPATED...BUT POSSIBLY THE GREATER IMPACT WILL BE HEAVY RAINFALL POTENTIAL AS THERE/S SUPPORT OF ONE OR MORE MCS/S PASSING THROUGH THE SANDHILLS REGION. STORM MOTION WILL BE ON THE SLOW SIDE...GENERALLY LESS THAN 20KTS...AND WITH PWATS INCREASING OVER AN INCH AND A THIRD...RAINFALL RATES OF AN INCH OR TWO AN HOUR WILL BE POSSIBLE. UPPER LOW PRESSURE TO BUILD EAST INTO THE PACIFIC NORTHWEST WEDNESDAY ALLOWING THE EASTWARD DEVELOPMENT OF A LOW AMPLITUDE TRANSITORY RIDGE. PRECIPITATION CHANCES CONTINUE ON WEDNESDAY AS THE NEXT WAVE EMBEDDED IN THE NOW QUASI-ZONAL FLOW IMPACTS THE REGION. TIMING AND PLACEMENT OF THE BETTER PRECIPITATION CHANCES WILL BE GENERALLY TIED TO THE LOCATION OF A LOW LEVEL FRONTAL BOUNDARY AND HOW CONVECTION FROM THE PREVIOUS DAY PLAYS OUT. AT THIS TIME THE MODELS ARE FAVORING NORTHERN NEBRASKA WITH THE HIGHER POP CHANCES /40 PERCENT/ WEDNESDAY AFTERNOON...WILL FOLLOW SUIT WITH THE FORECAST. THE AFOREMENTIONED RIDGE MAY EFFECTIVELY CAP THE REGION ON THURSDAY AS MIDLEVEL TEMPS WARM AOA 14C...AT THIS POINT WILL KEEP MOST OF THE CWA DRY THURSDAY WITH THE EXCEPTION BEING THURSDAY NIGHT ACROSS OUR NORTHERN BORDER WHERE RIDGE RIDING WAVE MAY SPARK CONVECTION. FOR LATE WEEK AND THE WEEKEND...FORECAST CONFIDENCE IS NOT QUITE THERE YET AS THE FINER DETAILS OF HOW THE WESTERN CONUS TROUGH WILL PLAY OUT ARE STILL AN ENIGMA. IN THE SYNOPTIC SCALE THERE REMAINS GOOD AGREEMENT OF A FAIRLY STRONG TROUGH ADVANCING INTO THE NORTHERN ROCKIES WITH MOST OF THE FAVORABLE UPPER LEVEL ENERGY TARGETING THE NORTHERN PLAINS. SOLID MOISTURE RETURN AND WARMING TEMPERATURES WILL BE IN PLACE ACROSS THE CENTRAL PLAINS...WITH A FRONTAL PASSAGE/SFC TROUGH FOR THE WEEKEND. STORMS...POSSIBLY SEVERE WILL ONCE AGAIN BE POSSIBLE....BUT WITH LACKING CONSISTENCY...WILL CAP POP CHANCES AT 40 PERCENT OR LESS THROUGH THE WEEKEND. AS FOR TEMPERATURES...A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE END OF THE WORK WEEK...WITH HIGHS GENERALLY IN THE 80S...LOWS WILL BE SEASONAL IN THE 50 AND 60S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1152 PM CDT SUN JUN 22 2014 ISOLATED THUNDERSTORMS ARE POSSIBLE IN THE VICINITY OF THE KLBF TERMINAL THROUGH 09Z MONDAY. CIGS MAY DROP DOWN TO 7000 FT AGL IN THE VICINITY OF THUNDERSTORMS. FOR MONDAY...CIGS AROUND 5000 FT AGL ARE EXPECTED WITH A SMALL THREAT FOR ISOLATED THUNDERSTORMS IN THE AFTERNOON HOURS. THE THUNDERSTORM THREAT WILL END ON MONDAY EVENING WITH CIGS INCREASING TO 15000 FT AGL. FOR THE KVTN TERMINAL...EXPECT BROKEN TO OVERCAST CIGS RANGING FROM 10000 TO 20000 FT AGL OVERNIGHT. CIGS WILL SCATTER OUT MONDAY MORNING...WITH BROKEN CIGS EXPECTED MONDAY AFTERNOON AND MONDAY EVENING WITH LEVELS AROUND 12000 FT AGL. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...JACOBS AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
100 AM CDT MON JUN 23 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 301 PM CDT SUN JUN 22 2014 THE PRIMARY SHORT TERM FORECAST CONCERN CENTERS AROUND THE CHANCE OF THUNDERSTORMS THIS AFTERNOON INTO TONIGHT. OVER THE LAST 8 HOURS HAVE GREATLY REDUCED THUNDERSTORM CHANCES FOR THIS AFTERNOON AND TONIGHT ACROSS OUR FORECAST AREA. THE GREATEST REDUCTION IN THUNDERSTORM CHANCES HAS BEEN ACROSS NEBRASKA. THERE IS MODEST TO EVEN FAIRLY GOOD INSTABILITY ACROSS THE FORECAST AREA ESPECIALLY ACROSS KANSAS...WITH LITTLE TO NO CIN. WIND SHEAR IS RATHER WEAK WITH DEEP LAYER 0-6 KM SHEAR OF LESS THAN 30 KTS. THE BIG ISSUE CENTERS AROUND FORCING OR THE LIFTING MECHANISM FOR ORGANIZED CONVECTION. FORCING MECHANISMS ACROSS THE REGION INCLUDE AN UPPER LEVEL SHORT WAVE TROUGH OVER IOWA...A SOUTHWARD SLIPPING SFC FRONTAL BOUNDARY ACROSS NORTHERN KANSAS...AND A VERY WEAK UPPER WAVE CENTERED OVER THE BLACK HILLS OF SOUTH DAKOTA EXTENDING INTO THE NEBRASKA PANHANDLE. THE SFC FRONT IS THE PRIMARY FORCING MECHANISM CURRENTLY LOCATED OVER OUR FORECAST AREA AND IT IS GRADUALLY SINKING SOUTH WHERE IT WILL EXIT OUR AREA BY LATER THIS EVENING. THEREFORE...THUNDERSTORMS SEEM MOST LIKELY LATE THIS AFTERNOON INTO EARLY THIS EVENING IN CLOSE PROXIMITY TO THE SFC FRONT OVER NORTHERN KANSAS AND THUS HAVE KEPT POPS AROUND 50/50 IN THESE SOUTHERN ZONES...WITH THE HIGHER POPS REALLY BEING SOUTH OF OUR FORECAST AREA TONIGHT. SOME FORECAST MODELS GENERATE CONVECTION ACROSS THE HIGH PLAINS TONIGHT IN ASSOCIATION WITH THE VERY WEAK UPPER WAVE...BUT 4 OUT OF 6 MODELS HAVE THIS PRECIPITATION DIEING OFF BEFORE REALLY REACHING OUR AREA TONIGHT. ONE OUTSIDE WRF RUN AND THE HRRR DO BRING CONVECTION FROM WESTERN PORTIONS OF NEBRASKA AND KANSAS INTO OUR FORECAST AREA LATE TONIGHT WHILE MOST MODELS DO NOT. WILL GO WITH THE MAJORITY GIVEN THERE IS NOT MUCH OF A LOW LEVEL JET TO HELP SUSTAIN CONVECTION TONIGHT ACROSS OUR FORECAST AREA. ANY THUNDERSTORMS THAT CAN FORM THIS AFTERNOON OR EVENING ACROSS KANSAS COULD BECOME SEVERE GIVEN THE HIGHER INSTABILITY ACROSS OUR SOUTHERN ZONES. MONDAY...MOST FORECAST MODELS INDICATE THAT WE WILL BE IN BETWEEN WEAK SHORT WAVE STORM SYSTEMS AND LIKELY DRY. TEMPERATURES WILL BE MILD WITH A LIGHT NORTHEAST WIND KEEPING THINGS A BIT COOLER THAN TODAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 301 PM CDT SUN JUN 22 2014 THE WEATHER PATTERN REMAINS UNSETTLED DURING THE EXTENDED PERIODS WITH INTERMITTENT CHANCES FOR THUNDERSTORMS. AN UPPER LOW PRESSURE SYSTEM WILL BE TRANSLATING SOUTHEAST FM CANADA TO THE UPPER MIDWEST REGION AT THE ONSET OF THE EXTENDED WITH THE FLOW ALOFT TRANSITIONING WEST NORTHWEST FOR A TIME AS ANOTHER TROUGH DIGS INTO THE PACIFIC NORTHWEST REGION. A SERIES OF WAVES EMBEDDED IN THE FLOW WILL AID IN TSTM DEVELOPMENT WITH TIMING/PLACEMENT DEPENDENT UPON WAVE TIMING AND BOUNDARY LOCATIONS AND BOUNDARY LOCATION WILL BE DEPENDENT UPON HOW CONVECTION UNFOLDS THE PREVIOUS DAY. IT IS DIFFICULT TO PINPOINT DETAILS ATTM AND WITH THE PROGRESSIVE PATTERN JUST CANNOT RULE OUT TSTM CHCS NEARLY EVERY DAY. CONVECTION MAY DEVELOP ALONG THE HIGH PLAINS AND ROLL EASTWARD...OR MAY INITIATE ALONG A BOUNDARY WITHIN THE AREA. SREF INSTABILITY PROGS INDICATE THE GREATER INSTABILITY MONDAY NIGHT WILL RESIDE ALONG THE HIGH PLAINS REGION...WHICH WILL BEGIN TO SPREAD EASTWARD ON TUESDAY...WITH MUCAPES INCREASING TO NEAR OR JUST ABOVE 1000 J/KG. WITH THE MORE MARGINAL INSTABILITY ON TUESDAY...NOT LOOKING FOR MUCH SEVERE WX JUST YET WITH INSTABILITY FURTHER INCREASING TUESDAY NIGHT INTO MID WEEK WITH RETURN FLOW...STRENGTHENING NOCTURNAL LLVL JET AND WAA/UPPER RIDGING AHEAD OF UPPER TROUGH IN THE PACIFIC NW. UPPER RIDGING SETTLES OVERHEAD FOR THE LATTER PART OF THE WORKWEEK AND MID LEVEL TEMPS INCREASE TO AROUND 14C SO CAP MAY LIMIT CONVECTION FOR A TIME. MODELS ARE NOT IN GREAT AGREEMENT ON THE TIMING/PROGRESSION OF THE WESTERN TROUGH AS IT PUSHES EAST THRU THE MOUNTAINS TOWARDS THE PLAINS AND WILL NEED TO MONITOR BUT CHCS FOR STORMS INCREASE AGAIN WITH THIS SYSTEM OVER THE WEEKEND OR EARLY NEXT WEEK. ALL BEING SAID...INTERMITTENT CHANCES FOR STORMS CONTINUE AND TEMPS LOOK FAIRLY SEASONAL ATTM. && .AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z MONDAY NIGHT) ISSUED AT 1259 AM CDT MON JUN 23 2014 VFR CONDITIONS ARE EXPECTED BEHIND A COLD FRONT WITH VARYING AMOUNTS OF MID TO UPPER LEVEL CLOUDINESS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...WESELY LONG TERM...FAY AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1202 AM CDT MON JUN 23 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 341 PM CDT SUN JUN 22 2014 AT 19Z...WATER VAPOR SHOWED QUASI-ZONAL FLOW ACROSS MUCH OF THE CONUS WITH AN UPPER LEVEL LOW SPINNING OVER THE CENTRAL SASKATCHEWAN/MANITOBA BORDER. MULTIPLE WEAK SHORTWAVES COULD BE PICKED OUT MOVING ACROSS THE ROCKIES...FROM MONTANA DOWN THROUGH NEW MEXICO. THE STRONGER SHORTWAVE WAS SEEN OVER WESTERN COLORADO AT MID AFTERNOON WHICH WILL IMPACT THE FORECAST FOR TONIGHT...WITH THE SECOND MORE DISTINCT SHORTWAVE SEEN OVER EASTERN IDAHO...WHICH WILL IMPACT THE FORECAST FOR MONDAY. AT THE SURFACE...A COLD FRONT WAS SITUATED FROM SOUTHWEST KANSAS INTO NORTHWEST MISSOURI. NORTH OF THIS FRONT COLD AIR HAD ADVECTED INTO NEBRASKA...WITH MID AFTERNOON TEMPERATURES GENERALLY IN THE 70S AND LOW 80S. DECENT LOW LEVEL MOISTURE DID REMAIN IN PLACE...AS DEWPOINTS ACROSS THE AREA WERE STILL IN THE UPPER 50S AND 60S. WITH THE MOISTURE IN PLACE AND STEEP LOW LEVEL LAPSE RATES...AN EXTENSIVE CUMULUS FIELD HAD DEVELOPED ACROSS WESTERN NEBRASKA. DESPITE DECENT SB INSTABILITY OF 1500-2500 J/KG WITH NO CAP...ANY SHOWERS AND THUNDERSTORMS HAVE HAD A PROBLEM MAINTAINING WITH NO ADDITIONAL FORCING IN PLACE. FOR THIS EVENING AND TONIGHT...ALTHOUGH THE HRRR IS INDICATING STORMS DEVELOPING OVER SOUTHWEST NEBRASKA AHEAD OF THE MAIN SYSTEM OVER THE ROCKIES...FEEL THIS ACTIVITY WILL BE WEAK WITH THE LACK OF FORCING FROM THE SHORTWAVE AND VERY LITTLE IF ANY FORCING COMING FROM ANY LOW LEVEL MOISTURE TRANSPORT. SO WILL FOCUS ON ACTIVITY MOVING OUT ONTO THE PLAINS WITH THE MAIN SHORTWAVE. AS THIS SHORTWAVE OVER WESTERN COLORADO MOVES EAST EXPECT FURTHER DEVELOPMENT OF CONVECTION ALONG THE FOOTHILLS AND INTO THE HIGH PLAINS. THE QUESTION WILL BE HOW FAR NORTH THE CONVECTION WILL DEVELOP. THE LATEST FEW RUNS OF THE HRRR INDICATE ACTIVITY DEVELOPING AS FAR NORTH AS SCOTTSBLUFF. THESE STORMS WOULD THEN MOVE SOUTHEAST ALONG A THETA-E GRADIENT. ALTHOUGH THERE IS SUFFICIENT INSTABILITY AND DEEP LAYER SHEAR WILL BE INCREASING...THE LOCAL AREA WILL BE ON THE NORTHERN FRINGE OF ANY ACTIVITY AND WITH THE BETTER FORCING OVER KANSAS EXPECT THE THREAT FOR ANY SEVERE STORMS TO STAY SOUTH OF THE AREA. FOR MONDAY THE SHORTWAVE TROUGH NOW OVER EASTERN IDAHO WILL MOVE ACROSS WYOMING AND THEN ACROSS NEBRASKA FROM NORTHWEST TO SOUTHEAST. NOT EXTREMELY CONFIDENT ON HOW MUCH COVERAGE OF SHOWERS AND THUNDERSTORMS THERE WILL BE AS THE AIRMASS WILL BE SLIGHTLY DRIER...WITH DEWPOINTS MAINLY IN THE 50S AND NO REAL SURGE OF DEEP MOISTURE ALOFT. AT THE PRESENT TIME THINK ANY CONVECTION WILL BE MORE ISOLATED TO SCATTERED IN NATURE. THE NEXT QUESTION IS WHERE THE CONVECTION WILL ACTUALLY BE. THE NAM SHOWS QPF ACROSS MUCH OF THE FORECAST AREA WHILE THE GFS/ECMWF ARE KEEPING IT MAINLY OVER THE PANHANDLE AND SOUTHWEST NEBRASKA. HAVE SIDED WITH THE GFS/ECMWF FOR TODAY AND HAVE LIMITED CHANCES FOR THE WESTERN AREAS. AS FOR HIGHS ON MONDAY...LOOKING FOR A SLIGHTLY COOLER DAY WITH HIGHS IN THE 70S AND LOW 80S AS COOLER AIR SLOWLY CONTINUES TO FILTER INTO THE AREA BEHIND THE UPPER LEVEL SYSTEM OVER SOUTHERN CANADA. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 341 PM CDT SUN JUN 22 2014 NORTHWEST FLOW ALOFT WILL PERSIST MONDAY NIGHT THROUGH TUESDAY NIGHT WITH THE PASSAGE OF TWO DISTINCT DISTURBANCES. MAINTAINED 30 POPS LATE MONDAY NIGHT ACROSS WESTERN ZONES...TO 40 POPS TUESDAY/TUESDAY NIGHT. PWAT VALUES FROM GFS INDICATE 120 TO NEAR 140 PERCENT OF NORMAL WITH DEEP LAYER SHEAR INCREASING TO 30 TO 40 KTS. THIS SUPPORTIVE OF STRONG THUNDERSTORMS TUESDAY AFTN/EVENING WITH LOCALLY HEAVY RAINFALL DUE TO SLOW STORM MOTION NEAR 10 KTS. SECOND DISTURBANCE FORECAST TO LIFT ACROSS LATE TUESDAY NIGHT AND WEDNESDAY WITH 40 POPS TUESDAY NIGHT...FOLLOWED BY 40 POPS FOR NCTRL WEDNESDAY. MAINLY 20 TO 30 POPS THURSDAY THROUGH SATURDAY. DUE TO WEAK RIDGING OVER THE REGION AND SWRLY FLOW TO OUR WEST WHICH MOVES IN BY FRIDAY NIGHT...MODEL AGREEMENT IN TIMING AND LOCATION IS RATHER POOR. TEMPERATURES HOWEVER WILL WARM FROM THE UPPER 70S TO LOWER 80S TUESDAY...MID 80S THURSDAY THROUGH SATURDAY TO AROUND 90 BY SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1152 PM CDT SUN JUN 22 2014 ISOLATED THUNDERSTORMS ARE POSSIBLE IN THE VICINITY OF THE KLBF TERMINAL THROUGH 09Z MONDAY. CIGS MAY DROP DOWN TO 7000 FT AGL IN THE VICINITY OF THUNDERSTORMS. FOR MONDAY...CIGS AROUND 5000 FT AGL ARE EXPECTED WITH A SMALL THREAT FOR ISOLATED THUNDERSTORMS IN THE AFTERNOON HOURS. THE THUNDERSTORM THREAT WILL END ON MONDAY EVENING WITH CIGS INCREASING TO 15000 FT AGL. FOR THE KVTN TERMINAL...EXPECT BROKEN TO OVERCAST CIGS RANGING FROM 10000 TO 20000 FT AGL OVERNIGHT. CIGS WILL SCATTER OUT MONDAY MORNING...WITH BROKEN CIGS EXPECTED MONDAY AFTERNOON AND MONDAY EVENING WITH LEVELS AROUND 12000 FT AGL. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BROOKS LONG TERM...ROBERG AVIATION...CLB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
343 AM CDT MON JUN 23 2014 .SYNOPSIS... ISSUED AT 324 AM CDT MON JUN 23 2014 REX BLOCKING OVER THE CANADIAN PRAIRIE IS FORECAST TO BREAK DOWN ON WEDNESDAY...BUT THERE IS GOOD AGREEMENT THAT THE NORTHEAST PACIFIC UPPER LEVEL LOW WILL BROADEN FURTHER INTO NORTHWESTERN CONUS...AND EVENTUALLY INTO THE NORTHERN PLAINS. SCATTERED SHOWERS AND THUNDERSTORMS WILL TRANSITION TO HIGHER CHANCES OF THUNDERSTORMS AS SOUTHWESTERLY FLOW ALOFT MOVES OVER THE DAKOTAS LATER THIS WEEK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT MON JUN 23 2014 SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST TODAY WITH PEAK HEATING...BUT THERE IS UNCERTAINTY ABOUT HOW MUCH INSTABILITY WILL DEVELOP. THE MOST RECENT TWO HRRR RUNS HAVE INCREASED THEIR COVERAGE OF THUNDERSTORMS EMBEDDED WITHIN RAIN SHOWERS. CAPPED THE COVERAGE OF THUNDERSTORMS TO SCATTERED FOR TODAY AND TONIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 324 AM CDT MON JUN 23 2014 JUST A REMNANT OF THE PERSISTENT UPPER LOW WILL REMAIN ACROSS NORTH DAKOTA ON TUESDAY. THIS UPPER FEATURE ACCOMPANIED BY AN ASSOCIATED SURFACE FRONTAL BOUNDARY WILL HELP FOCUS SHOWERS AND SCATTERED THUNDERSTORMS ACROSS THE CENTRAL AND NORTH TUESDAY AFTERNOON. TUESDAY NIGHT ACTIVITY WILL BE MINIMAL AS THE COLD FRONT REMAINS SOUTH OF THE STATE...BECOMING STATIONARY...TO RETURN EVENTUALLY WEDNESDAY NIGHT AND THURSDAY AS A WARM FRONTAL BOUNDARY IN ADVANCE OF A WESTERN UPPER TROUGH. THIS H500 TROUGH AND SURFACE WARM FRONT WILL BE THE FOCUS FOR AN ACTIVE THUNDERSTORM PERIOD THURSDAY NIGHT INTO FRIDAY NIGHT. MODELS SUGGEST SEVERAL MCS TYPE SYSTEMS SPREADING THUNDERSTORMS INTO THE REGION AND WILL BE MONITORING THE POTENTIAL FOR MODERATE TO HEAVY RAIN DURING THIS TIME FRAME. POPS REMAIN LIKELY FRIDAY NIGHT INTO SATURDAY FOR THIS. POPS TRAIL OFF INTO 20 TO 30S SUNDAY AFTER THE PASSAGE OF THE SHORTWAVE TROUGH/COLD FRONT. TEMPERATURES DURING THE EXTENDED LOOK NEAR OR SLIGHTLY BELOW NORMAL WITH HIGHS IN THE 70S TO AROUND 80. LOWS IN THE 50S TO NEAR 60. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 324 AM CDT MON JUN 23 2014 THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON...BUT CONFIDENCE IS TOO LOW TO NAIL DOWN TIMING AND COVERAGE. THE BEST CHANCE FOR THUNDERSTORMS IS AT KMOT...WITH KISN/KJMS TIED FOR SECOND. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SCHECK SHORT TERM...SCHECK LONG TERM...WAA AVIATION...SCHECK
AREA FORECAST DISCUSSION
NWS TULSA OK
344 AM CDT MON JUN 23 2014 .DISCUSSION... LARGE MCS ONGOING FROM TX PANHANDLE THROUGH CENTRAL OK WILL CONTINUE TO DEVELOP SOUTH AND EASTWARD THROUGH THE MORNING. WHILE THE EXACT EVOLUTION REMAINS TO BE SEEN...LATEST RAP DATA DEPICT A WELL DEVELOPED MCV WHICH IS FORECAST TO SHIFT EASTWARD TODAY WITHIN THE BASE OF THE LARGER SYNOPTIC SCALE TROUGH. THIS IS EXPECTED TO EITHER MAINTAIN ONGOING CONVECTION AND/OR AID IN REDEVELOPMENT LATER THIS AFTERNOON THUS HIGH PRECIP CHANCES AREAWIDE TODAY. THE SYNOPTIC FRONT WILL PUSH INTO THE REGION TONIGHT AND IS EXPECTED TO FOCUS ANY OVERNIGHT PRECIP TOWARD THE SOUTHEASTERN HALF OF THE FORECAST AREA. BEYOND TONIGHT THE AFOREMENTIONED BOUNDARY REMAINS STALLED ACROSS THE REGION WHILE PROFILES REMAIN MOIST AND LARGELY UNCAPPED. THIS WILL RESULT IN SEVERAL DAYS OF SCATTERED CONVECTION THROUGH MID WEEK. TEMPS DURING THIS TIMEFRAME ARE EXPECTED TO REMAIN NEAR OR BELOW NORMAL. THE PATTERN BEGINS TO TRANSITION TOWARD MORE DOMINANT UPPER RIDGING BY LATE WEEK THROUGH NEXT WEEKEND...WITH A TREND TOWARD LESSER PRECIP COVERAGE AND WARMER TEMPS. && .PRELIMINARY POINT TEMPS/POPS... TUL 84 67 87 70 / 80 40 20 20 FSM 84 69 86 69 / 70 60 30 20 MLC 84 68 85 69 / 80 60 40 30 BVO 83 65 87 67 / 80 30 10 10 FYV 80 65 83 66 / 60 60 20 20 BYV 81 65 83 66 / 70 60 20 20 MKO 83 67 86 68 / 70 50 30 20 MIO 83 66 86 68 / 70 40 10 10 F10 83 67 86 69 / 80 50 30 20 HHW 85 70 86 70 / 90 60 40 40 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ LONG TERM....07
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
551 AM EDT MON JUN 23 2014 .SYNOPSIS... A MOISTENING SOUTHERLY FLOW WILL DEVELOP AHEAD OF A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST. THE COLD FRONT WILL PUSH THROUGH THE STATE ON WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR LATE IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... OTHER THAN FOR PATCHY FOG...THE DAY WILL DAWN BRIGHT WITH JUST SOME THIN HIGH CLOUDS BLEEDING ACROSS FROM DYING CONVECTION OVER THE GR LAKES. WITH HIGH PRESSURE NOSING DOWN FROM THE NEW ENGLAND COAST ALL THE WAY TO THE CAROLINAS...SOUTHERLY FLOW ON THE RETURN SIDE WILL BRING STEADILY HIGHER DEWPOINTS NORTHWARD INTO THE REGION OVER THE NEXT COUPLE OF DAYS. AS WE HEAT UP TODAY...WE WILL SEE A STEADY EROSION OF THE STABILITY WITH THE RAP INDICATING MID LEVEL LAPSE RATES EXCEEDING 7C/KM BY EARLY AFTERNOON. HOWEVER CAPE IS EXPECTED TO BE LIMITED BY MID LEVEL DRY AIR OVER CENTRAL AND EASTERN AREAS...WITH THE BEST CHANCE OF POPPING A SHOWER OR STORM BEING OVER MY WESTERN ZONES. MOISTURE WILL BE A BIT DEEPER THERE...BUT EVEN SO A FAIRLY STRONG CAPPING INVERSION WILL BE HARD TO BREAK SO ACTIVITY SHOULD NOT BE WIDESPREAD. HIGHS TODAY LOOK TO BE PRETTY WELL CLUSTERED FROM THE UPPER 70S TO MID 80S...STARTING TO EDGE ABOVE NORMAL FOR A CHANGE. THE PROXIMITY OF THE WAVY FRONT ENTERING THE OHIO VALLEY TONIGHT WILL KEEP A SMALL CHANCE OF SHOWERS AND STORMS LINGERING OVER MY WESTERN AND NORTHWESTERN AREAS OVERNIGHT. IT WILL BE A MILD NIGHT IN THE 60S. && .SHORT TERM /TUESDAY/... TUESDAY WILL BE WARM AND MUGGY WITH AN INCREASING THREAT FOR CONVECTION THE DEEPER INTO THE DAY WE GET. SREF/GEFS BOTH BRING A SURGE OF ANOMALOUSLY HIGH PWATS WITH CAPES EXPECTED EXPECTED TO EXCEED 1000J OVER A WIDE AREA. SPC HAS PLACED US IN A SEE TEXT AREA MENTIONING...STEEP LOW-LEVEL LAPSE RATES MAY BE ENOUGH FOR MARGINALLY SEVERE WIND GUSTS ASSOCIATED WITH SHORT BOWING LINE SEGMENTS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE FRONTAL SYSTEM APPROACHING FROM THE MID WEST IS FORECAST TO BE RATHER WAVY AND COMPLEX...WITH THE POTENTIAL FOR IT TO LINGER OVER THE REGION LONGER THAN PREVIOUSLY INDICATED. BOTH THE GFS AND ECMWF SHOW A NEW WAVE FORMING OVER THE STATE WEDNESDAY...AT LEAST SUPPORTING THE IDEA OF KEEPING HIGH POPS IN THE FORECAST THROUGH THE DAY...BUT ALSO RAISING THE POSSIBILITY OF LOCALLY HEAVY RAINS FOCUSING ALONG THE SLOW MOVING FRONTAL BOUNDARY. DRIER AIR FINALLY LOOKS LIKE IT WILL MAKE A RETURN FOR THURSDAY- FRIDAY AS HIGH PRESSURE BUILDS ACROSS SOUTHERN CANADA JUST NORTH OF THE GREAT LAKES. THE COOL PUSH DOESN`T LOOK TERRIBLY ROBUST SO HIGHS SHOULD REMAIN CLOSE TO OR EVEN A BIT ABOVE NORMAL INTO NEXT WEEKEND. OPERATIONAL GFS/ECMWF DIFFER ON EVENTS FOR SATURDAY-SUNDAY TIMEFRAME WITH THE EXPECTED HANGING AROUND OF THE BOUNDARY THAT IS EXPECTED TO PASS ON WEDNESDAY. THE GFS CREATES QUITE A BIT OF PRECIP FOCUSED ON THE STRONG LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONTAL ZONE. THE ECMWF IS LESS EXCITED ABOUT THIS...KEEPING THE BOUNDARY WEAKER AND FURTHER SOUTH. I DIDN`T BITE TOO HARD ON THE MORE PESSIMISTIC GFS/GEFS...KEEPING JUST SMALL CHANCES OF PRECIP OVER THE NEXT WEEKEND. WORTH NOTING...LAST NIGHT THE LONGER RANGE GUIDANCE WANTED TO REALLY PUMP UP HEIGHTS OVER THE EASTERN US FOR EARLY NEXT WEEK. THE ECMWF HAS DONE A TOTAL FLIP-FLOP ON THIS NOW BRINGING AN UPPER LOW SLOWLY DOWN THE NEW ENGLAND COAST TO OFF NJ BY MONDAY...WITH UPPER HEIGHTS NOT NEARLY AS HIGH AS WAS ADVERTISED. THE GEFS SHOWS MORE RIDGING...BUT SIMILARLY SEEMS TO WANT TO BACK OFF THE IDEA OF A BIG SURGE IN THE SUBTROPICAL RIDGE IN THE EAST. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... NOT MUCH FOG SO FAR. MAY SEE A LITTLE AS THE SUN HEATS THINGS UP. MAINLY LOOKING A DRY DAY TODAY WITH VFR CONDITIONS. ENJOY...AS AT LEAST THE LATER PART OF TUESDAY INTO WED...WILL FEATURE SHOWERS AND THUNDERSTORMS...AS A SW FLOW OF MORE HUMID AIR WORKS IN...AHEAD OF A COLD FRONT FOR LATE WED. THERE WAS A FEW SHOWERS YESTERDAY AFT...GIVEN STEEP LOW LVL LAPSE RATES. THIS WILL BE THE CASE THE NEXT SEVERAL DAYS. A SHOWER WILL BE POSSIBLE AT BFD BEFORE 06Z TUE AM...BUT STILL THINK THE FIRST PART OF TUESDAY WILL BE MAINLY DRY IN MOST LOCATIONS. OUTLOOK... TUE-WED...SHRA/TSRA. LOCAL RESTRICTIONS LIKELY. THU-FRI...VFR. PERHAPS A SHOWER OR STORM LATE FRI. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
524 AM EDT MON JUN 23 2014 .SYNOPSIS... A MOISTENING SOUTHERLY FLOW WILL DEVELOP AHEAD OF A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST. THE COLD FRONT WILL PUSH THROUGH THE STATE ON WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR LATE IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... OTHER THAN FOR PATCHY FOG...THE DAY WILL DAWN BRIGHT WITH JUST SOME THIN HIGH CLOUDS BLEEDING ACROSS FROM DYING CONVECTION OVER THE GR LAKES. WITH HIGH PRESSURE NOSING DOWN FROM THE NEW ENGLAND COAST ALL THE WAY TO THE CAROLINAS...SOUTHERLY FLOW ON THE RETURN SIDE WILL BRING STEADILY HIGHER DEWPOINTS NORTHWARD INTO THE REGION OVER THE NEXT COUPLE OF DAYS. AS WE HEAT UP TODAY...WE WILL SEE A STEADY EROSION OF THE STABILITY WITH THE RAP INDICATING MID LEVEL LAPSE RATES EXCEEDING 7C/KM BY EARLY AFTERNOON. HOWEVER CAPE IS EXPECTED TO BE LIMITED BY MID LEVEL DRY AIR OVER CENTRAL AND EASTERN AREAS...WITH THE BEST CHANCE OF POPPING A SHOWER OR STORM BEING OVER MY WESTERN ZONES. MOISTURE WILL BE A BIT DEEPER THERE...BUT EVEN SO A FAIRLY STRONG CAPPING INVERSION WILL BE HARD TO BREAK SO ACTIVITY SHOULD NOT BE WIDESPREAD. HIGHS TODAY LOOK TO BE PRETTY WELL CLUSTERED FROM THE UPPER 70S TO MID 80S...STARTING TO EDGE ABOVE NORMAL FOR A CHANGE. THE PROXIMITY OF THE WAVY FRONT ENTERING THE OHIO VALLEY TONIGHT WILL KEEP A SMALL CHANCE OF SHOWERS AND STORMS LINGERING OVER MY WESTERN AND NORTHWESTERN AREAS OVERNIGHT. IT WILL BE A MILD NIGHT IN THE 60S. && .SHORT TERM /TUESDAY/... TUESDAY WILL BE WARM AND MUGGY WITH AN INCREASING THREAT FOR CONVECTION THE DEEPER INTO THE DAY WE GET. SREF/GEFS BOTH BRING A SURGE OF ANOMALOUSLY HIGH PWATS WITH CAPES EXPECTED EXPECTED TO EXCEED 1000J OVER A WIDE AREA. SPC HAS PLACED US IN A SEE TEXT AREA MENTIONING...STEEP LOW-LEVEL LAPSE RATES MAY BE ENOUGH FOR MARGINALLY SEVERE WIND GUSTS ASSOCIATED WITH SHORT BOWING LINE SEGMENTS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE FRONTAL SYSTEM APPROACHING FROM THE MID WEST IS FORECAST TO BE RATHER WAVY AND COMPLEX...WITH THE POTENTIAL FOR IT TO LINGER OVER THE REGION LONGER THAN PREVIOUSLY INDICATED. BOTH THE GFS AND ECMWF SHOW A NEW WAVE FORMING OVER THE STATE WEDNESDAY...AT LEAST SUPPORTING THE IDEA OF KEEPING HIGH POPS IN THE FORECAST THROUGH THE DAY...BUT ALSO RAISING THE POSSIBILITY OF LOCALLY HEAVY RAINS FOCUSING ALONG THE SLOW MOVING FRONTAL BOUNDARY. DRIER AIR FINALLY LOOKS LIKE IT WILL MAKE A RETURN FOR THURSDAY- FRIDAY AS HIGH PRESSURE BUILDS ACROSS SOUTHERN CANADA JUST NORTH OF THE GREAT LAKES. THE COOL PUSH DOESN`T LOOK TERRIBLY ROBUST SO HIGHS SHOULD REMAIN CLOSE TO OR EVEN A BIT ABOVE NORMAL INTO NEXT WEEKEND. OPERATIONAL GFS/ECMWF DIFFER ON EVENTS FOR SATURDAY-SUNDAY TIMEFRAME WITH THE EXPECTED HANGING AROUND OF THE BOUNDARY THAT IS EXPECTED TO PASS ON WEDNESDAY. THE GFS CREATES QUITE A BIT OF PRECIP FOCUSED ON THE STRONG LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONTAL ZONE. THE ECMWF IS LESS EXCITED ABOUT THIS...KEEPING THE BOUNDARY WEAKER AND FURTHER SOUTH. I DIDN`T BITE TOO HARD ON THE MORE PESSIMISTIC GFS/GEFS...KEEPING JUST SMALL CHANCES OF PRECIP OVER THE NEXT WEEKEND. WORTH NOTING...LAST NIGHT THE LONGER RANGE GUIDANCE WANTED TO REALLY PUMP UP HEIGHTS OVER THE EASTERN US FOR EARLY NEXT WEEK. THE ECMWF HAS DONE A TOTAL FLIP-FLOP ON THIS NOW BRINGING AN UPPER LOW SLOWLY DOWN THE NEW ENGLAND COAST TO OFF NJ BY MONDAY...WITH UPPER HEIGHTS NOT NEARLY AS HIGH AS WAS ADVERTISED. THE GEFS SHOWS MORE RIDGING...BUT SIMILARLY SEEMS TO WANT TO BACK OFF THE IDEA OF A BIG SURGE IN THE SUBTROPICAL RIDGE IN THE EAST. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... SOME CLDS FROM NEAR UNV...SE INTO THE MDT AREA. WAS A FEW DROPS OF RAIN AT MDT JUST BEFORE MIDNIGHT. ANYWAY...EXPECT SOME FOG OVERNIGHT...BUT NOT AS WIDESPREAD AS IT WAS LAST NIGHT. EARLIER DISCUSSION BELOW. AN ISOLATED SHOWER WILL REMAIN POSS THROUGH MID EVE...MAINLY IN THE LAUREL HIGHLANDS. VFR CONDITIONS WILL CONTINUE THROUGH THE EVENING HOURS...WITH SOME MVFR FOG DEVELOPING AFTER MIDNIGHT. WINDS WILL REMAIN LIGHT. VFR PERSISTS THROUGH MONDAY AS WINDS INCREASE TO 5-10 KTS FROM THE SOUTH. ISOLATED SHOWERS/POSS A TSTM ACROSS THE WESTERN HALF LATER MON AFT MAY BRING VERY LOCALIZED RESTRICTIONS. OUTLOOK... TUE-WED...SHRA/TSRA. LOCAL RESTRICTIONS LIKELY. THU...VFR. FRI...VFR TO MVFR WITH SCT AFTN -TSRA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1153 PM CDT SUN JUN 22 2014 .UPDATE... ISSUED AT 740 PM CDT SUN JUN 22 2014 CONCERNING THE FLASH FLOOD WATCH AND HEAVY RAIN POTENTIAL. TRENDS HAVE REALLY BEEN ON THE DECREASE FOR THE INGREDIENTS NEEDED FOR FLASH FLOODING TONIGHT. CURRENTLY A WEAKLY CONVERGENT TROUGH RUNS ABOUT ON I-35 THROUGH IA AND SRN MN THEN ANGLES TO NEAR KAXN IN MN. FURTHER WEST THE STABILIZING FRONT WAS EXTENDING FROM NW OF KFSD-KINL AND PROGRESSING SE WITH MID-50S DEWPOINTS /KABR 00Z RAOB WITH 0.70 INCH PRECIPITABLE WATER/. INDICATIONS ARE FOR A BIT FASTER COLD FRONTAL PUSH OVERNIGHT INTO THE MORNING HOURS WHICH MEANS MONDAY WILL NOT HAVE ANY FLASH FLOOD THREAT. PER THE 22.23Z RAP...THE 925 MB WINDS ARE ALL NW IN THE FORECAST AREA BY 15Z. IN FACT...MOST WINDS ON AND WEST OF THE MISS RIVER VEER AROUND TO NW AT 925 MB BY 08Z. THIS PROVIDES A MORE PROGRESSIVE SOLUTION TO ANY STORM ACTIVITY TONIGHT. CONCERNING THE STORMS EXPECTED TONIGHT...THE INSTABILITY AFTER THE AFTERNOON STORMS HAS SEVERELY IMPACTED THE CAPE AVAILABLE FOR HEAVY RAINFALL TONIGHT. RIGHT NOW THE FORECAST AREA IS IN THE HUNDREDS OF J/KG OF MUCAPE AND RADAR IS SHOWING LITTLE SIGN OF ANY ORGANIZED RAIN THREAT. THE COMPLEX NEAR ALBERT LEA MN HAS NOW DISSIPATED. THERE IS A BIT OF FRONTOGENESIS IN MID LEVELS THAT TRIES TO PRODUCE SOME LIFT FROM BLACK RIVER FALLS WI INTO NERN IA OVER NEXT SEVERAL HOURS. BUT WITH LIMITED OR DIMINISHING CAPES...ANY STORMS THAT FORM WILL STRUGGLE TO PRODUCE HEAVY RAIN. WITH THAT SAID..THE AIR MASS STILL HAS POTENT MOISTURE /KMPX 00Z RAOB 1.36 INCH PRECIPITABLE WATER/. IT IS JUST THAT THE ORGANIZATION AND INSTABILITY ARE NOT THERE FOR HEAVY RAIN. IN FACT...WILL ALSO ASSESS THE RAIN COVERAGE TONIGHT...IT LOOKS MUCH TOO HIGH PER LATEST HRRR RUNS AND 22.21Z HOPWRF RUN FROM MPX. BOTTOM LINE IS WE HAVE STARTED TO MESSAGE A REDUCED FLASH FLOOD THREAT...AND THE FLASH FLOOD WATCH WILL BE CANCELLED BY 9 PM UNLESS SOMETHING CHANGES. HAVE ALREADY REMOVED TAYLOR AND CLARK && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 334 PM CDT SUN JUN 22 2014 THE MAIN FOCUS THROUGH TOMORROW IS ON CONVECTIVE TRENDS AND WHETHER ANY FLASH FLOODING IS STILL POSSIBLE. AN MCV FROM OVERNIGHT HAS COME THROUGH MUCH OF THE REGION FROM LATE THIS MORNING INTO THE EARLY AFTERNOON HOURS AND HAS KICKED UP A BAND OF CONVECTION/RAIN OUT AHEAD OF IT. MUCH OF THE 22.12Z GUIDANCE HAS NOT DONE A VERY GOOD JOB OF PICKING UP ON THIS FEATURE AND STILL WANT TO DEVELOP A WIDE SWATH OF CONVECTION ACROSS THE REGION THIS EVENING. THE HRRR HAS DONE A DECENT JOB OF CAPTURING THIS CONVECTION AND CLEARS MOST OF THE REGION FROM THE WEST EARLY THIS EVENING. THE MOST UNSTABLE AIR MASS APPEARS TO STAY OUT AHEAD OF THE MCV...SO AM NOT EXPECTING MUCH IN THE WAY OF SEVERE DEVELOPMENT BEHIND IT. CONFIDENCE IS NOT VERY HIGH WITH HOW TONIGHT WILL PAN OUT WITH THE MAIN COLD FRONT STILL OFF TO THE WEST...SO WILL KEEP THE FLASH FLOOD WATCH GOING FOR THE TIME BEING AND LET THE EVENING PLAY OUT A BIT MORE BEFORE CANNING IT. THE 22.12Z NAM/GFS/GEM DID TREND FASTER WITH PUSHING THE PRECIPITATION/MID LEVEL TROUGH/SFC LOW OFF TO THE EAST TOMORROW MORNING...SO HAVE TRENDED A BIT FASTER WITH ENDING THE RAIN CHANCES TOMORROW. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 334 PM CDT SUN JUN 22 2014 A BRIEF DRY PERIOD IS EXPECTED MONDAY NIGHT INTO TUESDAY MORNING AS SUBSIDENT AIR COMES IN THE WAKE OF THE TROUGH. ANOTHER COLD FRONT WILL DROP DOWN FROM CANADA TUESDAY AFTERNOON AND BRING THE NEXT CHANCE OF RAIN ALONG WITH IT. SKINNY CAPE PROFILE WITH THIS FEATURE WITH LESS THAN 1000 J/KG OF MLCAPE EXPECTED...SO NOT THINKING THAT THIS WILL BE A SEVERE WEATHER PRODUCER AT THIS POINT. AFTER THAT FRONT DROPS TO THE SOUTH IT APPEARS TO STALL OUT FROM THE HIGH PLAINS ON DOWN SOUTHEAST THROUGH THE MID MISSISSIPPI RIVER VALLEY. CONFIDENCE NOT VERY HIGH WITH OUR PRECIPITATION CHANCES TOWARD THE END OF THE WEEK...BUT ALSO DID NOT HAVE MUCH OF A CHANCE TO DIG INTO THE DETAILS WITH CONVECTION ON GOING...SO HAVE GONE WITH THE CONSENSUS OF THE MODEL BLENDS FOR NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1153 PM CDT SUN JUN 22 2014 VFR CONDITIONS THROUGH THE PERIOD. THUNDERSTORMS FAR TO THE SOUTH ARE PROVIDING AN OVERCAST CEILING AT HIGHER ALTITUDES. THERE MAY BE SOME FOG IN THE VICINITY OF THE TAF SITES BUT FOR NOW HAVE LEFT IT OUT OF THE FORECAST WITH THE THICK HIGHER CLOUD KEEPING TEMPERATURES A BIT WARMER. THERE IS ALSO SOME CLOUD DEBRIS MOVING AROUND THAT ARE NOT ACCOUNTED FOR IN THE TAFS BUT SHOULD ONLY BE TRANSIENT AT THE AIRFIELDS TONIGHT. && .HYDROLOGY... ISSUED AT 334 PM CDT SUN JUN 22 2014 HEAVY RAINFALL FROM LAST WEEK HAS PRIMED THE GROUND FOR ADDITIONAL FLOODING WITH ANY STORMS THAT MAY MOVE THROUGH. THE STORMS TODAY HAD SOME BRIEFLY INTENSE RAINFALL RATES AT ABOUT 2 INCHES PER HOUR THOUGH THEY ONLY LASTED FOR ABOUT A HALF HOUR. MANY AREA RIVERS ARE STILL ELEVATED FROM THE RECENT RAINFALL AND WILL LIKELY STAY THAT WAY THROUGH THE WEEK. CONFIDENCE IS NOT VERY HIGH AT THIS POINT ABOUT WHETHER THE FLASH FLOOD WATCH IS STILL NECESSARY FOR TONIGHT...BUT WANT TO MAKE SURE THAT CONDITIONS WILL BE OKAY BEFORE DROPPING IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...BAUMGARDT HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1015 AM EDT MON JUN 23 2014 .DISCUSSION... LATEST SAT PICS SHOW A DISTINCT MOISTURE BNDRY ACRS THE FL PENINSULA WITH CONSIDERABLE CLOUD COVER CENTRAL/NRN PENINSULA...LITTLE IF ANY OVER THE S PENINSULA. MORNING SOUNDINGS CONFIRM THIS WITH PWAT VALUES ARND 2.0" AT KJAX/KMLB...DECREASING TO 1.6" AT KTBW...AND TO 1.4" AT KMFL. RUC ANALYSIS SHOWS THIS AS A BAND OF DRY H85-H50 AIR EXTENDING FROM THE NRN BAHAMAS INTO THE CENTRAL GOMEX. A FRONTAL TROF EXTENDING FROM THE CAROLINA COAST TO BERMUDA IS KEEPING THE AXIS OF THE H100-H70 SUBTROPICAL RIDGE SUPPRESSED OVER THE CENTRAL BAHAMAS/GOMEX. ALOFT...A WELL DEFINED TUTT AXIS EXTENDS FROM THE NW CARIB TO THE NRN BAHAMAS. THE FL PENINSULA LIES ON THE DESCENDING FLANK OF THE TUTT...WHILE THE POSITION OF THE LOW/MID LVL RIDGE AXIS WILL GENERATE A DEEP W/SW FLOW ACRS CENTRAL FL THAT WILL TAP THE DRIER MID LVL AIR UPSTREAM. WHILE THIS WILL LEAD TO DECREASING PWATS ACRS THE CWA...WITH SFC DEWPOINTS IN THE L/M70S...THIS WILL ONLY DELAY THE ONSET OF DIURNAL CONVECTION UNTIL MID AFTN. THIS...IN TURN WILL ALLOW GREATER SFC HEATING/DESTABILIZATION. SCT DIURNAL CONVECTION WILL FORM ALONG SEA/LAKE BREEZE BDRYS WITH WSW H85-H50 STEERING WINDS PUSHING ACTIVITY EWD ACROSS ECFL AT 10-15 MPH. INCREASING MOISTURE FROM S TO N WILL LEAD TO HIGHER PRECIP COVERAGE ALONG AND N OF I-4. WHILE DRY AIR ADVECTION AT MID LVLS WILL INCREASE TSTM GUST POTENTIAL...TEMP PROFILE IS UNIMPRESSIVE WITH LAPSE RATES THRU THE H85-H50 LYR BTWN 5.5-6.0C/KM...SVR THREAT REMAINS LOW. WRLY WINDS AND SLOWER INLAND PENETRATION OF THE EAST COAST SEA BREEZE WILL ALLOW MAX TEMPS TO WARM INTO THE L/M90S AREAWIDE. && .AVIATION... THRU 23/16Z...VFR ALL SITES. BTWN 23/16Z-23/18Z...SFC WNDSHFT FM W/SW TO E/SE AOB 12KTS ASSOCD WITH THE EAST COAST SEA BREEZE. BTWN 23/16Z-23/22Z...SCT MVFR SHRAS/IFR TSRAS ALL SITES...MORE NMRS N OF KVRB-KOBE...LIFR TSRAS PSBL BTWN KMLB-KDAB. BTWN 23/22Z-23/24Z... SCT SHRAS/TSRAS CONTG COASTAL SITES...MVFR CIGS/VSBYS IN -RA INTERIOR SITES. BTWN 24/00Z-24/02Z...SHRAS/TSRAS ENDING COASTAL SITES...BCMG VFR ALL SITES. && .MARINE... NO SIG CHANGES...LCL DATA BUOY/C-MAN NETWORK CONTINUES TO MEASURE A LIGHT TO GENTLE SW BREEZE WITH SEAS AOB 2FT. WINDS WILL SHIFT TO THE E/SE AOB 10KTS OVER THE NEARSHORE WATERS BY EARLY AFTN AS THE EAST COAST SEA BREEZE DVLPS. WRLY ENVIRONMENTAL FLOW WILL KEEP IT PINNED NEAR THE INTRACOASTAL WATERWAY THRU THE AFTN. DIURNAL CONVECTION TO DVLP BY MID AFTN WITH STORMS MVG OFFSHORE...POTENTIAL FOR WIND GUSTS ARND 35KTS. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...BRAGAW RADAR/IMPACT WX.......WEITLICH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
917 AM CDT MON JUN 23 2014 .DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * PERIODS OF SHOWERS AND BRIEF MVFR. LITTLE TSRA EXPECTED. * LOW IFR CONDITIONS EAST OF THE TERMINALS ALONG THE LAKESHORE. * WINDS VARIABLE BUT GENERALLY SOUTHERLY TO SOUTHWESTERLY. LENNING //DISCUSSION...UPDATED 12Z... THE PCPN FORECAST REMAINS THE MAIN CONCERN WITH SOME UNCERTAINTY CONTINUING WITH THE TSRA POTENTIAL. THE ENVIRONMENT OVER THE AREA REMAINS VERY MOIST AND SHOULD BECOME AT LEAST WEAKLY UNSTABLE THROUGH THE DAY. A MODERATE SHORTWAVE ALOFT HAS BEEN CONSISTENTLY FORECAST BY THE MODELS TO CROSS THE REGION THIS AFTERNOON...AND WILL BE ACCOMPANIED BY A WEAK COLD FRONT. FRONTAL FORCING WILL BE LOW AS THERE WILL BE ONLY A MINOR AIRMASS CHANGE WITH THE FRONTAL PASSAGE AND A WINDSHIFT FROM LIGHT SOUTHERLY WINDS TO LIGHT NWLY WINDS. THERE MAY BE A FEW GUSTS TO ARND 15KT IN THE WEAK WARM ADVECTION AHEAD OF THE FRONT...BUT WINDS SHOULD BE LESS THAN 10KT BEHIND THE FRONT. THE LATEST GUIDANCE AND SATELLITE TRENDS INDICATE A WEAKER SHORTWAVE ALOFT THAN PREVIOUSLY NOTED...SO HAVE BACKED OFF A BIT ON THE TSRA POTENTIAL IN THE TAFS. STILL FEEL THAT THE BEST TIMING WILL BE AT SOME POINT DURG THE AFTERNOON HOURS...BUT TSRA COULD END UP BEING MORE ISOLD/EMBEDDED THAN ORGANIZED SO HAVE GONE WITH VCTS WORDING. THIS SHOULD STILL COINCIDE WITH THE PASSAGE OF THE SHORTWAVE ALOFT AND THE WEAK COLD FRONT AT THE SURFACE. THE REMAINDER OF THE PERIOD SHOULD THEN BE DRY WITH NWLY WINDS LESS THAN 10KT AND VFR CIGS/VIS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN PERIODS OF SHOWERS. MEDIUM CONFIDENCE IN MVFR. * MEDIUM CONFIDENCE IN WIND DIRECTION...BUT HIGHER CONFIDENCE IN STAYING RELATIVELY LIGHT...BELOW 10KT SUSTAINED. * MEDIUM TO HIGH CONFIDENCE IN LIFR STAYING EAST OF THE TERMINALS. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. THURSDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE TSRA. OTHERWISE VFR. SUNDAY...SLIGHT CHANCE TSRA. OTHERWISE VFR. KREIN && .MARINE... 315 AM CDT BROAD HIGH PRESSURE EXTENDS FROM THE GREAT LAKES REGION ACROSS MUCH OF THE EAST COAST. THE RESULTANT LIGHT AND VARIABLE WINDS COMBINED WITH RESIDUAL HIGH DEWPOINT AIR OVER THE STILL VERY COLD LAKE WATERS HAS KEPT DENSE FOG IN PLACE. THE DENSE FOG WILL CONTINUE WHILE THE HIGH PRESSURE IS SLOWLY ERODED BY A TROUGH OF WEAK LOW PRESSURE AS IT MOVES ACROSS THE MISSISSIPPI VALLEY MONDAY MORNING. THE TROUGH AND AN ASSOCIATED WEAK COLD FRONT WILL MOVE ACROSS THE LAKE LATE MONDAY NIGHT TURNING WINDS FROM LIGHT AND VARIABLE TO WESTERLY AND NORTHWESTERLY...WHICH WILL BEGIN TO SCOUR OUT THE FOG FROM THE LAKE. A SECONDARY COLD FRONT WILL DROP DOWN THE LAKE TUESDAY TURNING WINDS NORTHERLY BRINGING AN END TO ANY RESIDUAL FOG AS DRIER AIR FILTERS OVER THE LAKE. HIGH PRESSURE WILL BUILD ACROSS THE UPPER LAKES WEDNESDAY AND THURSDAY KEEPING CONDITIONS OVER THE LAKE RELATIVELY QUIET...BUT BY THE END OF THE WEEK...STRENGTHENING SOUTHERLY WINDS OF 15 TO 25 KT WILL DEVELOP OVER THE LAKE AS THE HIGH MOVES OFF TO THE EAST AND ANOTHER TROUGH APPROACHES FROM THE WEST. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
646 AM CDT MON JUN 23 2014 .DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * SCT SHRA WITH OCNL MVFR CIGS THROUGH LATE MORNING. * SCT SHRA WITH ISOLD TSRA THIS AFTERNOON...POSSIBLY INTO EARLY EVENING. KREIN //DISCUSSION...UPDATED 12Z... THE PCPN FORECAST REMAINS THE MAIN CONCERN WITH SOME UNCERTAINTY CONTINUING WITH THE TSRA POTENTIAL. THE ENVIRONMENT OVER THE AREA REMAINS VERY MOIST AND SHOULD BECOME AT LEAST WEAKLY UNSTABLE THROUGH THE DAY. A MODERATE SHORTWAVE ALOFT HAS BEEN CONSISTENTLY FORECAST BY THE MODELS TO CROSS THE REGION THIS AFTERNOON...AND WILL BE ACCOMPANIED BY A WEAK COLD FRONT. FRONTAL FORCING WILL BE LOW AS THERE WILL BE ONLY A MINOR AIRMASS CHANGE WITH THE FRONTAL PASSAGE AND A WINDSHIFT FROM LIGHT SOUTHERLY WINDS TO LIGHT NWLY WINDS. THERE MAY BE A FEW GUSTS TO ARND 15KT IN THE WEAK WARM ADVECTION AHEAD OF THE FRONT...BUT WINDS SHOULD BE LESS THAN 10KT BEHIND THE FRONT. THE LATEST GUIDANCE AND SATELLITE TRENDS INDICATE A WEAKER SHORTWAVE ALOFT THAN PREVIOUSLY NOTED...SO HAVE BACKED OFF A BIT ON THE TSRA POTENTIAL IN THE TAFS. STILL FEEL THAT THE BEST TIMING WILL BE AT SOME POINT DURG THE AFTERNOON HOURS...BUT TSRA COULD END UP BEING MORE ISOLD/EMBEDDED THAN ORGANIZED SO HAVE GONE WITH VCTS WORDING. THIS SHOULD STILL COINCIDE WITH THE PASSAGE OF THE SHORTWAVE ALOFT AND THE WEAK COLD FRONT AT THE SURFACE. THE REMAINDER OF THE PERIOD SHOULD THEN BE DRY WITH NWLY WINDS LESS THAN 10KT AND VFR CIGS/VIS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 12Z... * LOW CONFIDENCE IN TSRA TIMING AND COVERAGE. * MEDIUM TO HIGH CONFIDENCE IN SCT SHRA THROUGH MUCH OF THE DAY. * LOW TO MEDIUM CONFIDENCE IN SHRA IMPACTS ON CIG/VIS. * MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. THURSDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE TSRA. OTHERWISE VFR. SUNDAY...SLIGHT CHANCE TSRA. OTHERWISE VFR. KREIN && .MARINE... 315 AM CDT BROAD HIGH PRESSURE EXTENDS FROM THE GREAT LAKES REGION ACROSS MUCH OF THE EAST COAST. THE RESULTANT LIGHT AND VARIABLE WINDS COMBINED WITH RESIDUAL HIGH DEWPOINT AIR OVER THE STILL VERY COLD LAKE WATERS HAS KEPT DENSE FOG IN PLACE. THE DENSE FOG WILL CONTINUE WHILE THE HIGH PRESSURE IS SLOWLY ERODED BY A TROUGH OF WEAK LOW PRESSURE AS IT MOVES ACROSS THE MISSISSIPPI VALLEY MONDAY MORNING. THE TROUGH AND AN ASSOCIATED WEAK COLD FRONT WILL MOVE ACROSS THE LAKE LATE MONDAY NIGHT TURNING WINDS FROM LIGHT AND VARIABLE TO WESTERLY AND NORTHWESTERLY...WHICH WILL BEGIN TO SCOUR OUT THE FOG FROM THE LAKE. A SECONDARY COLD FRONT WILL DROP DOWN THE LAKE TUESDAY TURNING WINDS NORTHERLY BRINGING AN END TO ANY RESIDUAL FOG AS DRIER AIR FILTERS OVER THE LAKE. HIGH PRESSURE WILL BUILD ACROSS THE UPPER LAKES WEDNESDAY AND THURSDAY KEEPING CONDITIONS OVER THE LAKE RELATIVELY QUIET...BUT BY THE END OF THE WEEK...STRENGTHENING SOUTHERLY WINDS OF 15 TO 25 KT WILL DEVELOP OVER THE LAKE AS THE HIGH MOVES OFF TO THE EAST AND ANOTHER TROUGH APPROACHES FROM THE WEST. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ 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...UPDATED
NWS GRAY ME
1009 AM EDT MON JUN 23 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFF THE NORTHEAST COAST TONIGHT. A COLD FRONT WILL SLOWLY DROP SOUTH FROM CANADA TUESDAY AND WILL STALL OVER THE REGION ON WEDNESDAY. THE FRONT WILL SLOWLY SHIFT OFFSHORE ON THURSDAY AND SEVERAL WEAK WAVES OF LOW PRESSURE WILL TRACK NORTHEAST ALONG IT THROUGH SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... UPDATE...SOME MINOR CHANGES TO ACCOUNT FOR LATEST OBSERVATIONAL TRENDS. PRES GRADIENT WILL SUPPORT ONSHORE FLOW INCREASING THROUGHOUT THE DAY...AND WINDS HAVE ALREADY TURNED SELY ALONG THE COAST ATTM. SHOULDN/T SEE TOO MUCH WARMING FOR THOSE AREAS FROM THIS POINT FORWARD TODAY. WARMING OF THE ELEVATED TERRAIN IS SUPPORTING CU DEVELOPMENT ATTM...WITH AN ISOLD SHRA NOT OUT OF THE QUESTION FOR THIS AFTERNOON. SPC WRF HAS SOME SHRA ACTIVITY...BUT LATEST HRRR NOT AS BULLISH ON CONVECTIVE PRECIP. WILL KEEP POP BELOW CHC ATTM. PREVIOUS DISCUSSION...HIGH PRESSURE WAS FIRMLY IN CONTROL OVER NORTHERN NEW ENGLAND EARLY THIS MORNING. THE WIND WAS CALM AREA WIDE. EVEN MOUNT WASHINGTON WAS REPORTING A WIND SPEED OF ONLY 1 MPH. 00Z GYX SOUNDING SHOWED DRY AIR AT THE SURFACE AND A MIXED LAYER EXTENDING ALL THE WAY TO 700 MB. ABOVE 700 MB A COUPLE OF SUBSIDENCE INVERSIONS WERE NOTED. IT WAS THIS STABLE LAYER THAT SERVED TO CAP THE WEAKLY UNSTABLE LOWER LEVELS AND TEND TO SQUASH THE HIGH BASED AFTERNOON CUMULUS CLOUDS BEFORE ANY SUBSTANTIAL SHOWERS COULD FORM. TODAY... EXPECT HIGH PRESSURE TO MOVE OFFSHORE INTO THE GULF OF MAINE... SETTING UP A RETURN SOUTHERLY FLOW / SEA BREEZE ACROSS THE AREA. EXPECT TEMPERATURES TO BE A COUPLE OF DEGREES WARMER THAN YESTERDAY... CONSIDERING THE WELL MIXED LAYER ABOVE THE SURFACE AND SLIGHTLY WARMING TEMPERATURES BENEATH RIDGING ALOFT. THIS TRANSLATES TO UPPER 70S TO LOW 80S EXCEPT FOR THE COASTAL AREAS WHERE TEMPERATURES WILL BE A FEW DEGREES COOLER. THE RETURN FLOW WILL BRING SOME SLIGHTLY GREATER MOISTURE INTO THE REGION. ESTIMATES FROM THE 00Z GYX SOUNDING ARE THAT IT WOULD TAKE A SURFACE DEW POINT IN THE MID 50S TO OVERCOME THE CAP ABOVE THE 700 MB LEVEL. DO NOT EXPECT DEW POINTS TO REACH THAT LEVEL TODAY AS RETURN FLOW IS NOT THAT STRONG... DEW POINTS ACROSS SOUTHERN NEW ENGLAND ARE ONLY IN THE LOW 50S... AND DEEP MIXING TO 700 MB WILL MAKE IT MORE DIFFICULT TO CONCENTRATE THIS MOISTURE RETURN IN THE LOW LEVELS ENOUGH TO GENERATE INSTABILITY. HOWEVER... IT IS POSSIBLE THAT HEATING IN THE MOUNTAINS MAY LEAD TO A FEW SHOWERS DEVELOPING THERE... WHERE IT WILL TAKE LESS SURFACE HEATING TO OVERCOME THE CAP. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... SOUTHERLY FLOW CONTINUES TONIGHT... WITH BETTER MOISTURE RETURN DEVELOPING ABOVE THE SURFACE INVERSION. COULD SEE SOME FOG IN VALLEY LOCATIONS WHERE TEMPERATURES COOL MORE EFFICIENTLY BEFORE THE HIGHER DEW POINT AIR MOVES IN LATER IN THE NIGHT. EXPECT LOWS ONLY IN THE LOW TO MID 50S DEW TO THE GREATER MOISTURE. ON TUESDAY... EXPECT TEMPERATURES ABOUT THE SAME AS MONDAY OR MAYBE A DEGREE OR TWO WARMER. UPPER TROUGH MOVING SOUTHEAST OUT OF HUDSON BAY WILL APPROACH THE AREA LATER IN THE DAY WITH A SURFACE COLD FRONT ASSOCIATED WITH IT. IN ADDITION... A SHORTWAVE TROUGH MOVING EAST OUT OF THE GREAT LAKES WILL ALSO CROSS NEW ENGLAND DURING THE AFTERNOON. THIS WILL PROVIDE SOME COOLING ALOFT (BETTER CHANCE OF INSTABILITY) AND LIFT AS THESE FEATURES MOVE TOWARD NORTHERN NEW ENGLAND. IN ADDITION... THE GREATER LOW LEVEL MOISTURE (MID TO UPPER 50S DEW POINTS) WILL ALSO SERVE TO INCREASE INSTABILITY ESPECIALLY IN THE MOUNTAINS. SHOULD SEE A FEW SHOWERS AND ISOLATED THUNDERSTORMS DEVELOPING BY EARLY AFTERNOON OVER THE HIGHER TERRAIN... WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS MOVING INTO THE AREA LATER IN THE AFTERNOON AND INTO TUESDAY EVENING AS THE UPPER TROUGH AND SURFACE FRONT MOVE TOWARD THE AREA. INSTABILITY SHOULD BE TOO WEAK FOR SEVERE THUNDERSTORMS TO BE A THREAT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... MODELS ARE SIMILAR IN MOVING COLD FRONT SLOWLY SOUTH FROM CANADA TUESDAY NIGHT. GFS IS GOING CRAZY WITH QPF AT THIS POINT WITH THE EURO BEING MORE REALISTIC. GFS MAY BE SUFFERING FROM SOME CONVECTIVE FEEDBACK. HOWEVER THAT SAID THE AIRMASS WILL BE VERY MOIST WITH PWATS NEAR 2 INCHES AND SURFACE DEWPOINTS IN THE MID 60S SO THERE IS A CHANCE FOR HEAVY RAIN ON THE ORDER OF 1 TO 3 INCHES. THE FRONT WILL ALSO SEE SEVERAL WAVES OF LOW PRESSURE RIPPLING NORTHEAST ALONG IT. COLD FRONT WILL FINALLY EXIT THE REGION LATE THURSDAY OR EARLY FRIDAY. HIGH PRESSURE WILL BEGIN TO BUILD IN FRIDAY. ANOTHER SYSTEM MAY APPROACH FROM THE SOUTHWEST LATE SATURDAY. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... SHORT TERM...VFR CONDITIONS TODAY AREA WIDE. THERE WILL BE A BETTER CHANCE FOR FOG TONIGHT AS LOW LEVEL MOISTURE WILL BE INCREASING. THE BEST CHANCE OF FOG WOULD BE AT LEBANON. LONG TERM...EXPECT IFR/LIFR LATE TUESDAY AND WEDNESDAY. MVFR/IFR NEAR THE COAST THURSDAY WITH IMPROVING CONDITIONS IN THE INTERIOR. VFR FRIDAY. MAY SEE MVFR BY LATE SATURDAY. && .MARINE... SHORT TERM...HIGH PRESSURE OVER THE WATERS BRINGS LIGHT WINDS AND NEARLY CALM SEAS. AS HIGH PRESSURE MOVES EAST... A SOUTHERLY FLOW WILL GRADUALLY INCREASE ON TUESDAY. LONG TERM...SMALL CRAFT ADVISORY MAY BE NEEDED TUESDAY NIGHT AND WEDNESDAY. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
627 AM EDT MON JUN 23 2014 .SYNOPSIS... THE WEATHER WILL BE A LITTLE WARMER AND MORE HUMID TODAY WITH AN ISOLATED STORM. THE BEST CHANCE FOR WET WEATHER WILL BE TUESDAY INTO WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... DRY WEATHER IS EXPECTED FOR THE START OF THE DAY...ALTHOUGH SOME HIGH CLOUDS WILL REMAIN OVER EASTERN OHIO. IN ADDITION...MANY LOCATIONS WILL HAVE SOME FOG. ANY LOCATION COULD SEE AN ISOLATED THUNDERSTORM TODAY...ALTHOUGH THE FOCUS WILL LIKELY REMAIN OVER THE LAUREL HIGHLANDS. A FEATURE NOT PREVIOUSLY SHOWN ON MODEL RUNS IS A SHORTWAVE THAT COULD DEVELOP OVER WESTERN OHIO LATE THIS AFTERNOON AND TRACK OVER NORTHWESTERN PENNSYLVANIA BY MIDNIGHT. WHILE THE NAM MOST CLEARLY DEPICTS THIS SHORTWAVE...THE END OF THE RAP MODEL RUN HINTS AT THIS DEVELOPMENT...AND VARIOUS HIGH RESOLUTION NMM RUNS ALSO DEVELOP THIS PRECIPITATION DURING THE EVENING HOURS. HAVE RAISED POPS SLIGHTLY DURING THE EVENING HOURS...DECREASING POPS AGAIN AFTER MIDNIGHT. WITH UPPER RIDGE BUILDING IN...TEMPS WILL BE ABOUT FIVE DEGREES WARMER TODAY THAN YESTERDAY. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... UNFORTUNATELY...THE 00Z GFS SUFFERS FROM CONVECTIVE FEEDBACK...SPINNING UP A SURFACE LOW ALONG THE APPROACHING COLD FRONT AND SHOWING UNREALISTIC PRECIPITATION AND VORTICITY MAXIMA. AS A RESULT...THE 00Z GFS WAS NOT USED THROUGH THIS PORTION OF THE FORECAST. PRIMARY CHANGE DURING THIS PORTION OF THE FORECAST WAS TO SLOW DOWN THE TIMING OF THE COLD FRONT. COMPARED TO MODEL RUNS FROM 24 HOURS AGO...FRONT APPEARS TO BE ABOUT 6 HOURS SLOWER IN ITS ARRIVAL AND PASSAGE WITH LATEST MODEL RUNS. THIS MEANS MANY LOCATIONS COULD REMAIN DRY TUESDAY MORNING...ALTHOUGH RAIN IS STILL EXPECTED EVERYWHERE BY TUESDAY EVENING. STRONG SHEAR VALUES REMAIN CONFINED TO THE LAKE ERIE SHORELINE...WHICH SHOULD KEEP THE THREAT FOR SEVERE STORMS FARTHER TO THE NORTH..BUT SOME STRONGER STORMS REMAIN POSSIBLE WITH MODEST INSTABILITY. BIGGER CONCERN COULD POSSIBLY BE HEAVY RAINFALL TUESDAY AFTERNOON AND NIGHT WITH PRECIPITABLE WATER VALUES RANGING FROM 1.5 INCHES ACROSS WV/MD RIDGES TO NEARLY 2 INCHES IN EASTERN OHIO AND NORTHWESTERN PENNSYLVANIA. THESE PWAT VALUES ARE NEAR THE 99TH PERCENTILE FOR JUNE...AND IF SHOWERS/STORM TRAIN ALONG THE FRONT...SOME LOCATIONS COULD SEE SEVERAL ROUNDS OF MODERATE TO HEAVY RAIN. HOWEVER...THE RELATIVELY DRY WEEKEND THAT JUST OCCURRED SHOULD HELP TO ALLEVIATE CONCERNS. MOST RAINFALL SHOULD FALL IN ADVANCE OF THE COLD FRONT...WHICH SHOULD ACTUALLY PASS OVER THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. RAIN SHOULD HANG ON FOR A WHILE INTO WEDNESDAY AFTERNOON ACROSS THE WV/MD RIDGES...BUT THINK THAT PRECIP CHANCES WILL DROP QUITE A BIT WEDNESDAY AFTERNOON...WITH NEARLY ALL LOCATIONS DRY BY WEDNESDAY NIGHT. A COUPLE OF WARM NIGHTS CAN BE EXPECTED DUE TO THE EXTENSIVE CLOUD COVER. DAYTIME HIGHS WILL BE SLIGHTLY ABOVE NORMAL TUESDAY AND SLIGHTLY BELOW NORMAL WEDNESDAY BEHIND THE COLD FRONT. && .LONG TERM /THURSDAY THROUGH SUNDAY/... KEEPING THURSDAY DRY WITH HIGH PRESSURE IN PLACE AND RELATIVELY LOW MOISTURE. FRONTAL BOUNDARY WILL RETURN NORTHWARD AS A WARM FRONT THURSDAY NIGHT/FRIDAY...BRINGING HIGHER PRECIPITABLE WATER VALUES BACK NORTHWARD. FROM HERE ON OUT...EXPECTING A DAILY CHANCE OF SHOWERS/THUNDERSTORMS AS H500 HEIGHTS SLOWLY RISE AND WE STAY IN A TYPICALLY WARM AND MOIST SUMMERTIME AIRMASS. DECIDED TO KEY ON DIURNAL POPS FOR NOW...EVEN THOUGH RIPPLES IN THE WESTERLIES MAY PROVIDE ENHANCED CHANCES. TEMPERATURES WILL FLOAT TO A BIT ABOVE SEASONAL LEVELS WITH TIME. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS THE FORECAST AREA EXPECTED TODAY. THE MAJORITY OF THE AFTERNOON WILL BE QUIET...BUT BY LATE AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS WILL EXPAND IN COVERAGE AS THE CAP ALOFT ERODES AND ALLOWS FOR DEEPER CONVECTIVE DEVELOPMENT. .OUTLOOK.../TUESDAY THROUGH SATURDAY/... THE BEST CHANCE FOR RESTRICTIONS WILL BE TUESDAY INTO WEDNESDAY WITH FRONTAL BOUNDARY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
753 AM EDT MON JUN 23 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 522 AM EDT MON JUN 23 2014 WV IMAGERY AND RUC ANALYSIS INDICATED WSW FLOW INTO THE NRN LAKES BETWEEN A MID/UPPER LEVEL TROUGH FROM MANITOBA INTO THE NRN PLAINS AND A RIDGE FROM THE OHIO VALLEY INTO QUEBEC. AT THE SFC...A WEAK TROUGH EXTENDED FROM NE MN INTO WRN WI. A MORE PROMINENT COLD FRONT STRETCHED FROM JAMES BAY TO NEAR WINNIPEG AHEAD OF HIGH PRESSURE OVER N CNTRL CANADA. FORCING FROM A WEAK SHRTWV IN NRN WI ALONG WITH AN AXIS OF HIGHER MOISTURE WITH PWAT VALUES TO 1.4 INCHES...WAS ENOUGH TO SUPPORT AN AREA OF SHOWERS OVER FROM SW UPPER MI INTO E CNTRL WI. TODAY...EXPECT THE SHRTWV AND AREA OF PCPN ONLY SLOWLY MOVE TO THE EAST THIS MORNING. WITH ONLY WEAK LARGE SCALE FORCING EXPECTED INTO THE AFTERNOON AND THE POTENTIAL FOR ANOTHER WEAK SHRTWV TO MOVE INTO THE AREA DURING INCREASED DAYTIME HEATING...THE FCST KEEPS MENTION OF JUST SCT SHRA WITH THE GREATEST COVERAGE EXPECTED OVER CNTRL UPPER MI. WITH TEMPS CLIMBING INTO THE MID 70S...THERE MAY BE ENOUGH INSTABILITY FOR SOME ISOLD/SCT TSRA AS MLCAPE VALUES CLIMB INTO THE 400-800 J/KG RANGE. TONIGHT...WITH THE LOSS OF DAYTIME HEATING...THE PCPN COVERAGE SHOULD DIMINISH. HOWEVER...INCREASED QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH MOVING INTO THE UPPER MS VALLEY WILL SUPPORT CONTINUED CHANCES FOR SCT SHOWERS AND A FEW TSRA. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 421 AM EDT MON JUN 23 2014 ON TUESDAY MORNING...THE MODELS ARE IN GOOD AGREEMENT IN SHOWING THE COLD FRONT MOVING OVER OR JUST SOUTH OF THE AREA. HOWEVER...THE 850MB TROUGH AXIS HANGS UP OVER LAKE SUPERIOR AS THERE IS LACK OF A SOUTHWARD PUSH DUE TO THE GENERAL ZONAL FLOW ALOFT. THIS WILL PROVIDE THE FOCUS FOR PRECIPITATION ON TUESDAY ESPECIALLY SINCE THE MODELS ARE IN EXCELLENT AGREEMENT IN SHOWING BROAD SYNOPTIC SUPPORT MOVING THRU AS THE 500MB TROUGH AXIS MOVES THROUGH. AS SUCH...THERE WILL LIKELY BE SCATTERED SHOWERS ACROSS THE ENTIRE FORECAST AREA THROUGH THE DAY DESPITE THE SURFACE FRONT BEING SOUTH OF THE REGION. THE NUMERICAL GUIDANCE ALSO SHOWS MUCAPE VALUES OF 500-1500 J/KG ACROSS THE REGION DURING THE DAY WITH MID LEVEL LAPSE RATES OF 6+ C/KM...ALLOWING FOR POSSIBLE THUNDERSTORM DEVELOPMENT. BEST CHANCES FOR THUNDER WOULD BE ACROSS THE SOUTHERN TIER WHERE SFC TEMPS WILL LIKELY BE IN THE LOWER-MID 70S AND IS WHERE THE BEST INSTABILITY WILL BE LOCATED. WILL NEED TO KEEP CHANCE POPS ACROSS THE EASTERN HALF OF THE FORECAST AREA DURING THE TUE EVENING HOURS AS WELL GIVEN REMAINING MID LEVEL FORCING AND REMAINING DAYTIME INSTABILITY. AT THIS TIME...WEDNESDAY IS EXPECTED TO REMAIN DRY AND COOL WITH THE 850MB TROUGH AND SFC FRONT REMAINING SOUTH OF THE AREA. STILL SOME WEAK TROUGHINESS AT 500MB AND AS SUCH WEAK MID LEVEL Q-VECTOR CONVERGENCE AND MOISTURE PERSISTS ACROSS THE AREA ALL DAY. HOWEVER...GIVEN LACK OF INSTABILITY AND VERY WEAK MID LEVEL LAPSE RATES COMBINED WITH ANTICYCLONIC LOW LEVELS WILL KEEP IT DRY FOR NOW. WOULD NOT BE SHOCKED TO SEE ISOLATED SHOWERS BUT CHANCES ARE NOT HIGH ENOUGH TO INCLUDE IN THE FORECAST AT TIME TIME. IN THE EXTENDED...ZONAL FLOW THROUGH THE PERIOD WILL MAKE TIMING OF PRECIPITATION SOMEWHAT DIFFICULT ESPECIALLY INTO THE WEEKEND. HOWEVER...THE LONGER RANGE MODELS ARE IN DECENT AGREEMENT ON THE BROAD SCALE FEATURES WHICH AT LEAST GIVES SOME BASIC CONFIDENCE ON WHEN THE BETTER CHANCES FOR RAIN WILL BE. ON THURSDAY...THE ECMWF AND GFS BOTH SHOW A COMPACT VORT MAX MOVING ACROSS THE AREA DURING THE DAY AS THE 850MB FRONT MOVES BACK NORTH. ALTHOUGH MOISTURE WILL BE VERY LIMITED...WILL INCLUDE CHANCE POPS FOR THE WESTERN HALF OF THE FORECAST AREA. BEHIND THIS VORT MAX...UPPER RIDGING BUILDS ACROSS THE AREA FOR FRIDAY WHICH SHOULD ALLOW FOR TEMPS TO RETURN TO NORMAL AS WELL AS DRY WEATHER. RETURN FLOW BEGINS IN EARNEST FOR THE WEEKEND WITH TEMPERATURES LIKELY TO RISE ABOVE NORMAL...AND PERHAPS A LITTLE MORE HUMIDITY AND SUMMER LIKE WEATHER. THIS WILL ALLOW FOR CHANCES OF SHOWERS AND STORMS EACH DAY...ALTHOUGH SUNDAY LOOKS LIKE THE BETTER CHANCE FOR SHOWERS AND STORMS GIVEN LOWERING HEIGHTS ACROSS THE AREA IN RESPONSE TO THE APPROACHING TROUGH. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 752 AM EDT MON JUN 23 2014 A MOIST AIRMASS WITH A WEAK DISTURBANCE MOVING THROUGH THE AREA WILL BRING SCT SHRA TODAY INTO THIS EVENING. HOWEVER...MAINLY VFR CONDITIONS ARE EXPECTED AS MOST OF THE RAIN WILL BE LIGHT. ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE...MAINLY THIS AFTERNOON AND EVENING. HOWEVER...THE PROBABILITY IS LOW ENOUGH TO LEAVE OUT MENTION FROM THE TAF. WITH LIGHT WINDS AND ABUNDANT LOW LEVEL MOISTURE REMAINING...FOG IS EXPECTED TO DEVELOP OVERNIGHT WITH VLIFR CONDITIONS POSSIBLE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 522 AM EDT MON JUN 23 2014 DENSE FOG WILL PERSIST OVER WESTERN LAKE SUPERIOR INTO THIS AFTERNOON. OTHERWISE...MAINLY LIGHT WINDS WILL PREVAIL INTO TONIGHT. AS A COLD FRONT MOVES THROUGH THE AREA ON TUESDAY...NORTHEAST WINDS WILL INCREASE TO 20 KNOTS WITH WAVES BUILDING TO AROUND 4 FEET. WINDS WILL DIMINISH TUE NIGHT INTO WED AS HIGH PRES BUILDS INTO THE REGION. MAINLY LIGHT WINDS AT OR BELOW 15 KNOTS ARE THEN EXPECTED THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR LSZ162-240>248-263>265. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MRD AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
929 AM CDT MON JUN 23 2014 .UPDATE... ISSUED AT 929 AM CDT MON JUN 23 2014 AS MCS CONTINUES TO WEAKEN AND MOVE OUT CI SHIELD ALSO PROGRESSING EWD. VISIBLE SAT PICS INDICATING POCKETS OF ELEVATED INSTABILITY IN THE FORM OF ENHANCEMENT OF AC LIKELY ON LEFTOVER BOUNDARIES. SHORT TERM MODELS CONTINUE TO SHOW SOME THREAT OF ISOLD SHOWERS AND MAYBE A COUPLE TSRA THROUGH THE MORNING INTO EARLY AFTERNOON LIKELY AS RESULT OF LOCAL CONVERGENCE ENHANCEMENT AS SUBTLE UPPER PV ANOMALY MOVES OUT OF SRN WY. WILL HAVE TO INVESTIGATE THIS A BIT MORE FOR THE AFTERNOON IN ORDER TO FURTHER REFINE BEST PRECIP CHANCES. OTHERWISE TEMPS AND DEW POINTS LOOK ON TRACK FOR NOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 319 AM CDT MON JUN 23 2014 ANOTHER MCS SHOULD DROP THROUGH THE CNTL HIGH PLAINS THIS AFTN. THE FORECAST USES 50 PERCENT OF THE RAP MODEL AND 50 PERCENT OF THE OTHER MODELS. THE ONGOING MCS APPEARS TO BE TAKING ON A CYCLONIC ROTATION WITH THE WARM SECTOR ACROSS SCNTL NEB AND THE UPPER LEVEL COLD POOL ACROSS SWRN NEB ATTM. RADAR TRENDS SUGGEST THIS SYSTEM COULD ROTATE THROUGH SCNTL NEB THIS MORNING AND SHOWERS AND TSTMS ARE POPPING LEFT AND RIGHT BETWEEN KLBF AND KLXN. FOR TONIGHT...NEBULOUS POPS ARE IN THE FCST ACROSS THE SANDHILLS AND AREAS SOUTH. GIVEN THE INABILITY OF THE SYNOPTIC SCALE MODELS TO PREDICT NOCTURNAL RAIN EVENTS OF LATE...THE FCST IS FORCED TO MAINTAIN A SCATTERED POP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 319 AM CDT MON JUN 23 2014 12Z TUESDAY AND BEYOND. NEAR DAILY PRECIPITATION CHANCES TO HEADLINE THE EXTENDED DISCUSSION THROUGH AT LEAST SATURDAY AS THE ACTIVE PATTERN CONTINUES. A BRIEF PERIOD OF NORTHWEST FLOW ALOFT WILL DIRECT TWO SUBTLE DISTURBANCES ACROSS THE CENTRAL PLAINS TUESDAY INTO WEDNESDAY. THE FIRST OF WHICH SHOULD BE EAST OF THE CWA BY 12Z TUESDAY. THERE REMAINS GOOD CONSENSUS HOWEVER THAT THUNDER CHANCES REMAIN THROUGH MUCH THE DAY AS THE NEXT DISTURBANCE FOLLOWS. THE ATMOSPHERE WILL CHARACTERIZED AS MODERATELY UNSTABLE...WITH GENERALLY 25-40 KTS OF DEEP LAYER SHEAR. STRONG TO SEVERE STORMS ARE ANTICIPATED...BUT POSSIBLY THE GREATER IMPACT WILL BE HEAVY RAINFALL POTENTIAL AS THERE/S SUPPORT OF ONE OR MORE MCS/S PASSING THROUGH THE SANDHILLS REGION. STORM MOTION WILL BE ON THE SLOW SIDE...GENERALLY LESS THAN 20KTS...AND WITH PWATS INCREASING OVER AN INCH AND A THIRD...RAINFALL RATES OF AN INCH OR TWO AN HOUR WILL BE POSSIBLE. UPPER LOW PRESSURE TO BUILD EAST INTO THE PACIFIC NORTHWEST WEDNESDAY ALLOWING THE EASTWARD DEVELOPMENT OF A LOW AMPLITUDE TRANSITORY RIDGE. PRECIPITATION CHANCES CONTINUE ON WEDNESDAY AS THE NEXT WAVE EMBEDDED IN THE NOW QUASI-ZONAL FLOW IMPACTS THE REGION. TIMING AND PLACEMENT OF THE BETTER PRECIPITATION CHANCES WILL BE GENERALLY TIED TO THE LOCATION OF A LOW LEVEL FRONTAL BOUNDARY AND HOW CONVECTION FROM THE PREVIOUS DAY PLAYS OUT. AT THIS TIME THE MODELS ARE FAVORING NORTHERN NEBRASKA WITH THE HIGHER POP CHANCES /40 PERCENT/ WEDNESDAY AFTERNOON...WILL FOLLOW SUIT WITH THE FORECAST. THE AFOREMENTIONED RIDGE MAY EFFECTIVELY CAP THE REGION ON THURSDAY AS MIDLEVEL TEMPS WARM AOA 14C...AT THIS POINT WILL KEEP MOST OF THE CWA DRY THURSDAY WITH THE EXCEPTION BEING THURSDAY NIGHT ACROSS OUR NORTHERN BORDER WHERE RIDGE RIDING WAVE MAY SPARK CONVECTION. FOR LATE WEEK AND THE WEEKEND...FORECAST CONFIDENCE IS NOT QUITE THERE YET AS THE FINER DETAILS OF HOW THE WESTERN CONUS TROUGH WILL PLAY OUT ARE STILL AN ENIGMA. IN THE SYNOPTIC SCALE THERE REMAINS GOOD AGREEMENT OF A FAIRLY STRONG TROUGH ADVANCING INTO THE NORTHERN ROCKIES WITH MOST OF THE FAVORABLE UPPER LEVEL ENERGY TARGETING THE NORTHERN PLAINS. SOLID MOISTURE RETURN AND WARMING TEMPERATURES WILL BE IN PLACE ACROSS THE CENTRAL PLAINS...WITH A FRONTAL PASSAGE/SFC TROUGH FOR THE WEEKEND. STORMS...POSSIBLY SEVERE WILL ONCE AGAIN BE POSSIBLE....BUT WITH LACKING CONSISTENCY...WILL CAP POP CHANCES AT 40 PERCENT OR LESS THROUGH THE WEEKEND. AS FOR TEMPERATURES...A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE END OF THE WORK WEEK...WITH HIGHS GENERALLY IN THE 80S...LOWS WILL BE SEASONAL IN THE 50 AND 60S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 611 AM CDT MON JUN 23 2014 VFR IS EXPECTED EAST OF HIGHWAY 83 TODAY. SCATTERED TSTM ACTIVITY IS EXPECTED WEST OF HIGHWAY 83...MAINLY FROM 18Z ONWARD AS STORMS DEVELOP NORTH AND MOVE SOUTH. TONIGHT...THE FORECAST IS UNCERTAIN AS THE MODELS SUGGEST A SECOND AREA OF TSTMS WILL DEVELOP ACROSS THE CNTL SANDHILLS AND CONTINUE THROUGHOUT THE NIGHT. LATER FORECASTS USING THE RAP MODEL WILL HOPEFULLY CLARIFY THIS AS THE SYNOPTIC SCALE MODELS HAVE SHOWN POOR SKILL FORECASTING STORM DEVELOPMENT LATELY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JWS SHORT TERM...CDC LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
612 AM CDT MON JUN 23 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 319 AM CDT MON JUN 23 2014 ANOTHER MCS SHOULD DROP THROUGH THE CNTL HIGH PLAINS THIS AFTN. THE FORECAST USES 50 PERCENT OF THE RAP MODEL AND 50 PERCENT OF THE OTHER MODELS. THE ONGOING MCS APPEARS TO BE TAKING ON A CYCLONIC ROTATION WITH THE WARM SECTOR ACROSS SCNTL NEB AND THE UPPER LEVEL COLD POOL ACROSS SWRN NEB ATTM. RADAR TRENDS SUGGEST THIS SYSTEM COULD ROTATE THROUGH SCNTL NEB THIS MORNING AND SHOWERS AND TSTMS ARE POPPING LEFT AND RIGHT BETWEEN KLBF AND KLXN. FOR TONIGHT...NEBULOUS POPS ARE IN THE FCST ACROSS THE SANDHILLS AND AREAS SOUTH. GIVEN THE INABILITY OF THE SYNOPTIC SCALE MODELS TO PREDICT NOCTURNAL RAIN EVENTS OF LATE...THE FCST IS FORCED TO MAINTAIN A SCATTERED POP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 319 AM CDT MON JUN 23 2014 12Z TUESDAY AND BEYOND. NEAR DAILY PRECIPITATION CHANCES TO HEADLINE THE EXTENDED DISCUSSION THROUGH AT LEAST SATURDAY AS THE ACTIVE PATTERN CONTINUES. A BRIEF PERIOD OF NORTHWEST FLOW ALOFT WILL DIRECT TWO SUBTLE DISTURBANCES ACROSS THE CENTRAL PLAINS TUESDAY INTO WEDNESDAY. THE FIRST OF WHICH SHOULD BE EAST OF THE CWA BY 12Z TUESDAY. THERE REMAINS GOOD CONSENSUS HOWEVER THAT THUNDER CHANCES REMAIN THROUGH MUCH THE DAY AS THE NEXT DISTURBANCE FOLLOWS. THE ATMOSPHERE WILL CHARACTERIZED AS MODERATELY UNSTABLE...WITH GENERALLY 25-40 KTS OF DEEP LAYER SHEAR. STRONG TO SEVERE STORMS ARE ANTICIPATED...BUT POSSIBLY THE GREATER IMPACT WILL BE HEAVY RAINFALL POTENTIAL AS THERE/S SUPPORT OF ONE OR MORE MCS/S PASSING THROUGH THE SANDHILLS REGION. STORM MOTION WILL BE ON THE SLOW SIDE...GENERALLY LESS THAN 20KTS...AND WITH PWATS INCREASING OVER AN INCH AND A THIRD...RAINFALL RATES OF AN INCH OR TWO AN HOUR WILL BE POSSIBLE. UPPER LOW PRESSURE TO BUILD EAST INTO THE PACIFIC NORTHWEST WEDNESDAY ALLOWING THE EASTWARD DEVELOPMENT OF A LOW AMPLITUDE TRANSITORY RIDGE. PRECIPITATION CHANCES CONTINUE ON WEDNESDAY AS THE NEXT WAVE EMBEDDED IN THE NOW QUASI-ZONAL FLOW IMPACTS THE REGION. TIMING AND PLACEMENT OF THE BETTER PRECIPITATION CHANCES WILL BE GENERALLY TIED TO THE LOCATION OF A LOW LEVEL FRONTAL BOUNDARY AND HOW CONVECTION FROM THE PREVIOUS DAY PLAYS OUT. AT THIS TIME THE MODELS ARE FAVORING NORTHERN NEBRASKA WITH THE HIGHER POP CHANCES /40 PERCENT/ WEDNESDAY AFTERNOON...WILL FOLLOW SUIT WITH THE FORECAST. THE AFOREMENTIONED RIDGE MAY EFFECTIVELY CAP THE REGION ON THURSDAY AS MIDLEVEL TEMPS WARM AOA 14C...AT THIS POINT WILL KEEP MOST OF THE CWA DRY THURSDAY WITH THE EXCEPTION BEING THURSDAY NIGHT ACROSS OUR NORTHERN BORDER WHERE RIDGE RIDING WAVE MAY SPARK CONVECTION. FOR LATE WEEK AND THE WEEKEND...FORECAST CONFIDENCE IS NOT QUITE THERE YET AS THE FINER DETAILS OF HOW THE WESTERN CONUS TROUGH WILL PLAY OUT ARE STILL AN ENIGMA. IN THE SYNOPTIC SCALE THERE REMAINS GOOD AGREEMENT OF A FAIRLY STRONG TROUGH ADVANCING INTO THE NORTHERN ROCKIES WITH MOST OF THE FAVORABLE UPPER LEVEL ENERGY TARGETING THE NORTHERN PLAINS. SOLID MOISTURE RETURN AND WARMING TEMPERATURES WILL BE IN PLACE ACROSS THE CENTRAL PLAINS...WITH A FRONTAL PASSAGE/SFC TROUGH FOR THE WEEKEND. STORMS...POSSIBLY SEVERE WILL ONCE AGAIN BE POSSIBLE....BUT WITH LACKING CONSISTENCY...WILL CAP POP CHANCES AT 40 PERCENT OR LESS THROUGH THE WEEKEND. AS FOR TEMPERATURES...A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE END OF THE WORK WEEK...WITH HIGHS GENERALLY IN THE 80S...LOWS WILL BE SEASONAL IN THE 50 AND 60S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 611 AM CDT MON JUN 23 2014 VFR IS EXPECTED EAST OF HIGHWAY 83 TODAY. SCATTERED TSTM ACTIVITY IS EXPECTED WEST OF HIGHWAY 83...MAINLY FROM 18Z ONWARD AS STORMS DEVELOP NORTH AND MOVE SOUTH. TONIGHT...THE FORECAST IS UNCERTAIN AS THE MODELS SUGGEST A SECOND AREA OF TSTMS WILL DEVELOP ACROSS THE CNTL SANDHILLS AND CONTINUE THROUGHOUT THE NIGHT. LATER FORECASTS USING THE RAP MODEL WILL HOPEFULLY CLARIFY THIS AS THE SYNOPTIC SCALE MODELS HAVE SHOWN POOR SKILL FORECASTING STORM DEVELOPMENT LATELY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
855 AM CDT MON JUN 23 2014 .SYNOPSIS... ISSUED AT 324 AM CDT MON JUN 23 2014 REX BLOCKING OVER THE CANADIAN PRAIRIE IS FORECAST TO BREAK DOWN ON WEDNESDAY...BUT THERE IS GOOD AGREEMENT THAT THE NORTHEAST PACIFIC UPPER LEVEL LOW WILL BROADEN FURTHER INTO NORTHWESTERN CONUS...AND EVENTUALLY INTO THE NORTHERN PLAINS. SCATTERED SHOWERS AND THUNDERSTORMS WILL TRANSITION TO HIGHER CHANCES OF THUNDERSTORMS AS SOUTHWESTERLY FLOW ALOFT MOVES OVER THE DAKOTAS LATER THIS WEEK. && .UPDATE... ISSUED AT 841 AM CDT MON JUN 23 2014 CURRENT FORECAST REMAINS IN PRETTY GOOD SHAPE WITH UPPER LOW/TROF NEAR LAKE WINNIPEG CONTINUING TO SAG TO THE SOUTHEAST WHILE COOL FRONT WORKS ITS WAY INTO THE AREA. STILL EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP FROM NORTH TO SOUTH TODAY AS THESE FEATURES WORK THEIR WAY INTO THE STATE. UPDATE ISSUED AT 639 AM CDT MON JUN 23 2014 CYCLONIC FLOW ALOFT WITH SHORTWAVE TROUGH MOVING THROUGH SOUTHWEST NORTH DAKOTA. THIS GENERATING HIGH CLOUDS AND SOME VIRGA WITH NO PRECIP SO FAR REACHING THE GROUND. OTHERWISE MAIN FEATURE TODAY WILL BE THE UPPER LEVEL OW ACROSS SOUTHERN CANADA WHICH WILL MOVE SOUTH TODAY AND TONIGHT BRINGING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT MON JUN 23 2014 SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST TODAY WITH PEAK HEATING...BUT THERE IS UNCERTAINTY ABOUT HOW MUCH INSTABILITY WILL DEVELOP. THE MOST RECENT TWO HRRR RUNS HAVE INCREASED THEIR COVERAGE OF THUNDERSTORMS EMBEDDED WITHIN RAIN SHOWERS. CAPPED THE COVERAGE OF THUNDERSTORMS TO SCATTERED FOR TODAY AND TONIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 324 AM CDT MON JUN 23 2014 JUST A REMNANT OF THE PERSISTENT UPPER LOW WILL REMAIN ACROSS NORTH DAKOTA ON TUESDAY. THIS UPPER FEATURE ACCOMPANIED BY AN ASSOCIATED SURFACE FRONTAL BOUNDARY WILL HELP FOCUS SHOWERS AND SCATTERED THUNDERSTORMS ACROSS THE CENTRAL AND NORTH TUESDAY AFTERNOON. TUESDAY NIGHT ACTIVITY WILL BE MINIMAL AS THE COLD FRONT REMAINS SOUTH OF THE STATE...BECOMING STATIONARY...TO RETURN EVENTUALLY WEDNESDAY NIGHT AND THURSDAY AS A WARM FRONTAL BOUNDARY IN ADVANCE OF A WESTERN UPPER TROUGH. THIS H500 TROUGH AND SURFACE WARM FRONT WILL BE THE FOCUS FOR AN ACTIVE THUNDERSTORM PERIOD THURSDAY NIGHT INTO FRIDAY NIGHT. MODELS SUGGEST SEVERAL MCS TYPE SYSTEMS SPREADING THUNDERSTORMS INTO THE REGION AND WILL BE MONITORING THE POTENTIAL FOR MODERATE TO HEAVY RAIN DURING THIS TIME FRAME. POPS REMAIN LIKELY FRIDAY NIGHT INTO SATURDAY FOR THIS. POPS TRAIL OFF INTO 20 TO 30S SUNDAY AFTER THE PASSAGE OF THE SHORTWAVE TROUGH/COLD FRONT. TEMPERATURES DURING THE EXTENDED LOOK NEAR OR SLIGHTLY BELOW NORMAL WITH HIGHS IN THE 70S TO AROUND 80. LOWS IN THE 50S TO NEAR 60. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 639 AM CDT MON JUN 23 2014 THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON...BUT CONFIDENCE IS TOO LOW TO NAIL DOWN TIMING AND COVERAGE. THE BEST CHANCE FOR THUNDERSTORMS IS AT KMOT. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJS SYNOPSIS...SCHECK SHORT TERM...SCHECK LONG TERM...WAA AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
647 AM CDT MON JUN 23 2014 .SYNOPSIS... ISSUED AT 324 AM CDT MON JUN 23 2014 REX BLOCKING OVER THE CANADIAN PRAIRIE IS FORECAST TO BREAK DOWN ON WEDNESDAY...BUT THERE IS GOOD AGREEMENT THAT THE NORTHEAST PACIFIC UPPER LEVEL LOW WILL BROADEN FURTHER INTO NORTHWESTERN CONUS...AND EVENTUALLY INTO THE NORTHERN PLAINS. SCATTERED SHOWERS AND THUNDERSTORMS WILL TRANSITION TO HIGHER CHANCES OF THUNDERSTORMS AS SOUTHWESTERLY FLOW ALOFT MOVES OVER THE DAKOTAS LATER THIS WEEK. && .UPDATE... ISSUED AT 639 AM CDT MON JUN 23 2014 CYCLONIC FLOW ALOFT WITH SHORTWAVE TROUGH MOVING THROUGH SOUTHWEST NORTH DAKOTA. THIS GENERATING HIGH CLOUDS AND SOME VIRGA WITH NO PRECIP SO FAR REACHING THE GROUND. OTHERWISE MAIN FEATURE TODAY WILL BE THE UPPER LEVEL OW ACROSS SOUTHERN CANADA WHICH WILL MOVE SOUTH TODAY AND TONIGHT BRINGING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT MON JUN 23 2014 SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST TODAY WITH PEAK HEATING...BUT THERE IS UNCERTAINTY ABOUT HOW MUCH INSTABILITY WILL DEVELOP. THE MOST RECENT TWO HRRR RUNS HAVE INCREASED THEIR COVERAGE OF THUNDERSTORMS EMBEDDED WITHIN RAIN SHOWERS. CAPPED THE COVERAGE OF THUNDERSTORMS TO SCATTERED FOR TODAY AND TONIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 324 AM CDT MON JUN 23 2014 JUST A REMNANT OF THE PERSISTENT UPPER LOW WILL REMAIN ACROSS NORTH DAKOTA ON TUESDAY. THIS UPPER FEATURE ACCOMPANIED BY AN ASSOCIATED SURFACE FRONTAL BOUNDARY WILL HELP FOCUS SHOWERS AND SCATTERED THUNDERSTORMS ACROSS THE CENTRAL AND NORTH TUESDAY AFTERNOON. TUESDAY NIGHT ACTIVITY WILL BE MINIMAL AS THE COLD FRONT REMAINS SOUTH OF THE STATE...BECOMING STATIONARY...TO RETURN EVENTUALLY WEDNESDAY NIGHT AND THURSDAY AS A WARM FRONTAL BOUNDARY IN ADVANCE OF A WESTERN UPPER TROUGH. THIS H500 TROUGH AND SURFACE WARM FRONT WILL BE THE FOCUS FOR AN ACTIVE THUNDERSTORM PERIOD THURSDAY NIGHT INTO FRIDAY NIGHT. MODELS SUGGEST SEVERAL MCS TYPE SYSTEMS SPREADING THUNDERSTORMS INTO THE REGION AND WILL BE MONITORING THE POTENTIAL FOR MODERATE TO HEAVY RAIN DURING THIS TIME FRAME. POPS REMAIN LIKELY FRIDAY NIGHT INTO SATURDAY FOR THIS. POPS TRAIL OFF INTO 20 TO 30S SUNDAY AFTER THE PASSAGE OF THE SHORTWAVE TROUGH/COLD FRONT. TEMPERATURES DURING THE EXTENDED LOOK NEAR OR SLIGHTLY BELOW NORMAL WITH HIGHS IN THE 70S TO AROUND 80. LOWS IN THE 50S TO NEAR 60. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 639 AM CDT MON JUN 23 2014 THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON...BUT CONFIDENCE IS TOO LOW TO NAIL DOWN TIMING AND COVERAGE. THE BEST CHANCE FOR THUNDERSTORMS IS AT KMOT. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SYNOPSIS...SCHECK SHORT TERM...SCHECK LONG TERM...WAA AVIATION...WAA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
939 AM EDT MON JUN 23 2014 .SYNOPSIS... A WARM FRONT WILL MOVE ACROSS THE REGION THIS AFTERNOON. A COLD FRONT WILL MOVE ACROSS NORTHERN OHIO AND NORTHWEST PENNSYLVANIA TUESDAY NIGHT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WARM FRONT CONTINUES TO PUSH NORTHEAST TOWARD THE AREA AND WAS CURRENTLY LOCATED OVER SOUTHWEST OHIO. SOME SHOWER AND THUNDERSTORM ACTIVITY WAS OVER NORTHERN INDIANA AND SOUTHERN MICHIGAN AT THIS TIME. THIS ACTIVITY WILL MOVE NORTHEAST INTO MICHIGAN WITH TIME. LATEST HRRR GUIDANCE SHOWS LITTLE THREAT EARLY THIS AFTERNOON FOR SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE WESTERN PORTIONS OF THE FORECAST AREA. HOWEVER...INCREASING DEW POINTS WERE TAKING PLACE OVER THE WEST ALONG WITH ABUNDANT SUNSHINE. CAPE IS ALSO INCREASING AS WELL. CUMULUS CLOUDS ARE BEGINNING TO FORM SO WILL LEAVE A MENTION OF AT LEAST A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS IN THE WEST AND THEN PROGRESS IT EAST AS THE AFTERNOON OCCURS. SO FAR...TEMPERATURES LOOK REASONABLE SO NO ADJUSTMENTS THERE. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... A COLD FRONT WILL SLOWLY APPROACH THE FORECAST AREA ON TUESDAY. WITH MUCH OF THE FORECAST AREA IN THE WARM SECTOR SCATTERED THUNDERSTORMS ARE NOT OUT OF THE QUESTION AT ANY TIME. THE 00Z RUN OF THE MODELS INDICATED THE COLD FRONT WILL PUSH ACROSS THE FORECAST AREA TUESDAY NIGHT. I WILL BEGIN TO INCREASE THE PROBABILITY OF PRECIPITATION CHANCES TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. THE GFS IS TRYING TO SHOW A WAVE DEVELOP ON THE FRONT ON TUESDAY. THIS SCENARIO MAY BE OVER DONE AND I AM LEANING MORE TOWARDS THE NAM SOLUTION. THE MODELS INDICATE A SECONDARY TROF WEDNESDAY MORNING...SO I WILL HOLD ON TO A LOW CHANCE OF PRECIPITATION WEDNESDAY. && .LONG TERM /FRIDAY THROUGH SUNDAY/... FOLLOWED WPC THROUGH THE LONG TERM PERIOD WHICH FAVORS CLOSER TO THE ECMWF. GENERALLY AM EXPECTING AN UPPER RIDGE FROM THE TENNESSEE VALLEY INTO THE OHIO VALLEY WITH HIGH PRESSURE ACROSS THE AREA OR TO THE SOUTHEAST. TEMPS SEASONAL TO SLIGHTLY ABOVE. WITH CHANCE OR SLIGHT CHANCE POPS THROUGH THE PERIOD. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... WARM FRONT TO OUR WEST AND SOUTH WILL MOVE EAST REACHING NEAR A TOL-MFD-CMH LINE BY 00Z. NO CHANGES IN EXPECTATIONS IN THAT WITH THE FRONT MOVING INTO THE AREA...EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP THIS AFTERNOON. ALSO TONIGHT WITH MORE MOISTURE IN THE AREA TOOK VISIBILITIES DOWN TO AT LEAST MVFR IN HAZE/FOG WITH SHOWERS. OUTLOOK...NON VFR POSSIBLE MON NIGHT THRU FRI IN SCT SHOWERS AND THUNDERSTORMS AS WELL AS POSSIBLE MORNING FOG/MIST. && .MARINE... HIGH PRESSURE MOVING EAST OF THE LAKES WILL SUPPORT A SOUTHEAST FLOW TODAY INTO TONIGHT AHEAD OF A WARM FRONT. THE WARM FRONT WILL MOVE ONTO THE WESTERN BASIN THIS EVENING AND BISECT THE LAKE TUESDAY MORNING BEFORE MOVING EAST IN THE AFTERNOON. WINDS WILL TURN SOUTHWEST AFTER THE WARM FRONT PASSES. A COLD FRONT WILL FOLLOW TUESDAY NIGHT...DROPPING SOUTHEAST OF THE LAKE BY WEDNESDAY MORNING. WINDS WILL TURN NORTHWEST BEHIND THE COLD FRONT. HIGH PRESSURE WILL BUILD ACROSS THE LAKE THURSDAY...MOVING EAST ON FRIDAY. WINDS SHOULD REMAIN GENERALLY LIGHT THROUGH THE PERIOD OUTSIDE OF ANY CONVECTIVE ACTIVITY SO AM EXPECTING TO REMAIN WELL BELOW SMALL CRAFT LEVELS THROUGHOUT THE FORECAST. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...GARNET NEAR TERM...LOMBARDY SHORT TERM...GARNET LONG TERM...TK AVIATION...TK MARINE...TK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
934 AM EDT MON JUN 23 2014 .SYNOPSIS... CONVECTION CHANCES INCREASE SLOWLY THROUGH TUESDAY AS A COLD FRONT APPROACHES AND ARRIVES WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... A FEW SHOWERS EXITING THE FORECAST AREA UP INTO THE WEST VIRGINIA NORTHERN PANHANDLE THIS MORNING. A QUASI STATIONARY WARM FRONT SITS TO OUR WEST ACROSS CENTRAL KY AND OH. ATMOSPHERE IS CURRENTLY WEAKLY UNSTABLE...AND WITH A LACK OF SIGNIFICANT TRIGGER THEN CHANCES FOR CONVECTIVE INITIATION LOW TO START THE PERIOD. EXPECT TERRAIN TO BE MAIN DRIVER AS TO WHERE WE SEE CONVECTIVE DEVELOPMENT TODAY AND CURRENT HRRR RUNS SEEM TO SUPPORT THIS TREND. MORE MOISTURE DUE TO ARRIVE LATE THIS AFTERNOON AND TONIGHT WITH PW VALUES INCREASING TO ABOUT 1.7 INCHES BY TUESDAY MORNING. SLIGHT RAMP UP IN POPS...ESPECIALLY OVER THE EASTERN MOUNTAINS TO START...THEN PROGRESSING IN FROM THE WEST AS FRONT MAKES CLOSER APPROACH LOOKS LIKE A GOOD FORECAST TREND AND THIS COVERED IN CURRENT PACKAGE. NO SIGNIFICANT CHANGES PLANNED. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... A VERY WARM AND HUMID AIRMASS...AND A VIGOROUS LEAD SHORT WAVE AHEAD OF AN APPROACHING COLD FRONT...WILL ACT TO BRING WIDESPREAD SHOWERS AND THUNDERSTORMS MAINLY TUESDAY AFTERNOON AND TUESDAY NIGHT. MODELS AGREE PRETTY WELL ON THE TIMING OF THE LEAD WAVE AND GOOD PROSPECTS FOR RAIN. TEMPERATURES WILL NOT BE AS HIGH TUESDAY DUE TO THE CLOUDS AND SHOWERS...BUT SHOULD STILL REACH THE LOWER TO MID 80S...AND IT WILL REMAIN QUITE HUMID. TEMPS TUESDAY NIGHT WILL BE WARM WITH TEMPERATURES STRUGGLING TO DROP BELOW 70. AS FAR AS THE FRONT IS CONCERNED...MODELS DIFFER ON WHETHER THE FRONT IS STRONG ENOUGH TO ACTUALLY MOVE EASTWARD ACROSS THE AREA BEHIND THE SHORT WAVE...AS FLOW ALOFT TURNS MORE WESTERLY OR NORTHWESTERLY. THE GFS AND CMC MODELS MANAGE TO DRIVE THE FRONT EAST OF THE AREA LATER WEDNESDAY...WITH THE NAM AND EURO MODELS SLOWLY DISSIPATING THE FRONT AS IT MOVE INTO THE AREA WEDNESDAY. IT WILL...IN ANY CASE...LAG BEHIND THE MAIN SHORT WAVE WHICH DEPARTS WEDNESDAY MORNING. DESPITE MUCH OF THE UPPER DYNAMICS DEPARTING WITH THE SHORT WAVE...AND WHETHER THE FRONT MAKES IT OR DISSIPATES...THERE WILL BE A WARM AND HUMID AIRMASS AHEAD OF THE FRONT TO CONTINUE A CHANCE OF SHOWERS AND STORMS WEDNESDAY. THEREAFTER...ENOUGH DRIER AIR ALOFT FINALLY MOVES IN FOR THURSDAY AND MUCH OF FRIDAY TO MAKE MOST OF THE AREA RAIN FREE. WHETHER THE FRONT MAKES IT OR NOT...THERE WILL NOT BE MUCH OF A TEMPERATURE DIFFERENCE FOR HIGHS..WITH TEMPS STILL REACHING INTO THE 80S. && .LONG TERM /FRIDAY THROUGH SUNDAY/... A SOMEWHAT TYPICAL LATE-JUNE PATTERN WILL CONTINUE IN THE EXTENDED PERIOD...CHARACTERIZED BY WARM AND MUGGY DAYS WITH AT LEAST A SLIGHT CHANCE OF A SHOWER AND/OR THUNDERSTORM EVERY DAY. HIGHER CHANCES OF PRECIP ARE CENTERED ON TWO DISTURBANCES...ONE ON FRIDAY AND THE OTHER NEAR WEEKEND/S END INTO SUNDAY NIGHT/EARLY MON. AFOREMENTIONED TEMPERATURES WILL BE NEAR SEASONAL...WITH NO REAL HEAT WAVES OR COOL PERIODS FORESEEN. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... WILL BE GETTING INTO SLIGHTLY BETTER CHANCES FOR SHOWERS AND STORMS TODAY...BUT NONE HIGH ENOUGH TO WARRANT TSRA IN THE PREVAILING. HAVE ALSO TRIED TO USE THE VCTS/CB SPARINGLY AS WELL. OTHERWISE...LOOKING AT 4-5KFT CU DECK FORMING TODAY...WITH MOUNTAIN CONVECTION BEGINNING EARLIER IN THE AFTERNOON THAN LOWLAND AREAS...WHERE FORMATION IS EXPECTED TO BE AFTER 20Z. BY NOT GOING WITH ANY PREVAILING TSRA...AN AMD OR TOW MAY BE NEEDED AS CONVECTION BEGINS TO SHOW ITS HAND. FOG TONIGHT IS IN QUESTION DUE TO EXPECTED CLOUD COVER. HAVE KEPT IT MODEST WITH THIS TAF ISSUANCE. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND COVERAGE OF SHOWERS AND STORMS MAY NEED PREVAILING OR TEMPO IN THE TAF. 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 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H M M CKB CONSISTENCY H H H H H H H H H H M H AFTER 12Z TUESDAY... IFR POSSIBLE IN IN THUNDERSTORMS TUESDAY INTO WEDNESDAY AND STRATUS/FOG AT NIGHT FOR SITES RECEIVING RAIN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JMV/26 NEAR TERM...KMC SHORT TERM...JMV LONG TERM...50 AVIATION...26
AREA FORECAST DISCUSSION
NWS TULSA OK
615 AM CDT MON JUN 23 2014 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. COMPLEX OF THUNDERSTORMS WILL MOVE ACROSS SOUTHEAST OK AND POSSIBLY INTO WEST CENTRAL ARKANSAS EARLY THIS MORNING...WITH MORE SCATTERED ACTIVITY ELSEWHERE. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TO RE-DEVELOP BY AFTERNOON IN MOIST AND UNSTABLE AIRMASS...MOSTLY ENDING A LITTLE AFTER 00Z. PERIODS OF MVFR CONDITIONS EXPECTED WITH SHOWERS AND THUNDERSTORMS. && .PREV DISCUSSION... /ISSUED 344 AM CDT MON JUN 23 2014/ DISCUSSION... LARGE MCS ONGOING FROM TX PANHANDLE THROUGH CENTRAL OK WILL CONTINUE TO DEVELOP SOUTH AND EASTWARD THROUGH THE MORNING. WHILE THE EXACT EVOLUTION REMAINS TO BE SEEN...LATEST RAP DATA DEPICT A WELL DEVELOPED MCV WHICH IS FORECAST TO SHIFT EASTWARD TODAY WITHIN THE BASE OF THE LARGER SYNOPTIC SCALE TROUGH. THIS IS EXPECTED TO EITHER MAINTAIN ONGOING CONVECTION AND/OR AID IN REDEVELOPMENT LATER THIS AFTERNOON THUS HIGH PRECIP CHANCES AREAWIDE TODAY. THE SYNOPTIC FRONT WILL PUSH INTO THE REGION TONIGHT AND IS EXPECTED TO FOCUS ANY OVERNIGHT PRECIP TOWARD THE SOUTHEASTERN HALF OF THE FORECAST AREA. BEYOND TONIGHT THE AFOREMENTIONED BOUNDARY REMAINS STALLED ACROSS THE REGION WHILE PROFILES REMAIN MOIST AND LARGELY UNCAPPED. THIS WILL RESULT IN SEVERAL DAYS OF SCATTERED CONVECTION THROUGH MID WEEK. TEMPS DURING THIS TIMEFRAME ARE EXPECTED TO REMAIN NEAR OR BELOW NORMAL. THE PATTERN BEGINS TO TRANSITION TOWARD MORE DOMINANT UPPER RIDGING BY LATE WEEK THROUGH NEXT WEEKEND...WITH A TREND TOWARD LESSER PRECIP COVERAGE AND WARMER TEMPS. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...14 LONG TERM....07 AVIATION...14
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1059 AM EDT MON JUN 23 2014 .SYNOPSIS... A MOISTENING SOUTHERLY FLOW WILL DEVELOP AHEAD OF A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST. THE COLD FRONT WILL PUSH THROUGH THE STATE ON WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR LATE IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... GOOD FIELD OF CUMULUS FRACTUS/HUMULUS THIS MORNING AS THE BOUNDARY LAYER MOISTURE AND PATCHY FOG LIFTED. AS THIS TRIES TO BURN OFF AND THIN...SOME HIGH CLOUDS TO WEST WILL DRIFT OVER THE REGION. STILL MOSTLY SUNNY IN SOUTH IN EASTERN AREAS THOUGH SATELLITE DOES IMPLY THIN CIRRUS OVER MORE NORTHERN AREAS. BACKED OFF A BIT ON THE CONVECTION IN WEST. MODELS CONTINUE TO SHOW THE FRONT TO OUR WEST SLOWING DOWN. 13Z RAP SHOWS WEAKER AND MORE ISOLATED CONVECTION. OVERNIGHT BEST CHANCE OF ANY SHOWERS WOULD BE OVER THE WESTERN MOUNTAINS. BUT ONLY CHANCE AND SLIGHT CHANCE AT THIS TIME. && .SHORT TERM /TUESDAY/... THEME FOR TUESDAY SEEMS SLOWER FRONT AND MOISTURE SURGE INTO PA...09Z SREF LESS ROBUST WITH QPF/POPS IN WESTERN PA AND MORE OPTIMISTIC OF MOSTLY RAIN FREE DAY IN SOUTHEASTERN PA. COULD BE A MORE CLOUDY DAY. THIS IS DUE TO SLOWER PROGRESSION OF FRONT AND PW PLUME TO OUR WEST. THIS SLOWER...DRIER THEME IS RELATED TO STRONG AND SLOW TO ERODE SURFACE RIDGE AND 500 HPA RIDGE. HARD FOR FRONTS TO PUSH INTO RIDGES THIS TIME OF YEAR. THE SREF SHOWS LIKELY POPS AS DOES FORECAST IN WESTERN AND NORTHWESTERN AREAS TUESDAY. BUT ONLY SLIGHT CHANCE IN SOUTHEAST. MODELS CONTINUE TO WANT TO DEFER HIGHER RAINFALL PROBS UNTIL WEDNESDAY AS RIDGE SHOULD SLOWLY YIELD. UNLESS YOUR BAILING HAY THIS WEEK...WE NEED RAIN WITH THIS SYSTEM AS THE GROWING RIDGE LATER THIS WEEK AND NEXT COULD PUT US INTO A MORE AIR MASS FORCED CONVECTIVE REGIME. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE FRONTAL SYSTEM APPROACHING FROM THE MID WEST IS FORECAST TO BE RATHER WAVY AND COMPLEX...WITH THE POTENTIAL FOR IT TO LINGER OVER THE REGION LONGER THAN PREVIOUSLY INDICATED. BOTH THE GFS AND ECMWF SHOW A NEW WAVE FORMING OVER THE STATE WEDNESDAY...AT LEAST SUPPORTING THE IDEA OF KEEPING HIGH POPS IN THE FORECAST THROUGH THE DAY...BUT ALSO RAISING THE POSSIBILITY OF LOCALLY HEAVY RAINS FOCUSING ALONG THE SLOW MOVING FRONTAL BOUNDARY. DRIER AIR FINALLY LOOKS LIKE IT WILL MAKE A RETURN FOR THURSDAY- FRIDAY AS HIGH PRESSURE BUILDS ACROSS SOUTHERN CANADA JUST NORTH OF THE GREAT LAKES. THE COOL PUSH DOESN`T LOOK TERRIBLY ROBUST SO HIGHS SHOULD REMAIN CLOSE TO OR EVEN A BIT ABOVE NORMAL INTO NEXT WEEKEND. OPERATIONAL GFS/ECMWF DIFFER ON EVENTS FOR SATURDAY-SUNDAY TIMEFRAME WITH THE EXPECTED HANGING AROUND OF THE BOUNDARY THAT IS EXPECTED TO PASS ON WEDNESDAY. THE GFS CREATES QUITE A BIT OF PRECIP FOCUSED ON THE STRONG LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONTAL ZONE. THE ECMWF IS LESS EXCITED ABOUT THIS...KEEPING THE BOUNDARY WEAKER AND FURTHER SOUTH. I DIDN`T BITE TOO HARD ON THE MORE PESSIMISTIC GFS/GEFS...KEEPING JUST SMALL CHANCES OF PRECIP OVER THE NEXT WEEKEND. WORTH NOTING...LAST NIGHT THE LONGER RANGE GUIDANCE WANTED TO REALLY PUMP UP HEIGHTS OVER THE EASTERN US FOR EARLY NEXT WEEK. THE ECMWF HAS DONE A TOTAL FLIP-FLOP ON THIS NOW BRINGING AN UPPER LOW SLOWLY DOWN THE NEW ENGLAND COAST TO OFF NJ BY MONDAY...WITH UPPER HEIGHTS NOT NEARLY AS HIGH AS WAS ADVERTISED. THE GEFS SHOWS MORE RIDGING...BUT SIMILARLY SEEMS TO WANT TO BACK OFF THE IDEA OF A BIG SURGE IN THE SUBTROPICAL RIDGE IN THE EAST. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... HAD FOG FOR A SHORT TIME AT UNIV. NOW AT LNS. OTHERWISE...MAINLY LOOKING A DRY DAY TODAY WITH VFR CONDITIONS. ENJOY...AS AT LEAST THE LATER PART OF TUESDAY INTO WED...WILL FEATURE SHOWERS AND THUNDERSTORMS...AS A SW FLOW OF MORE HUMID AIR WORKS IN...AHEAD OF A COLD FRONT FOR LATE WED. THERE WAS A FEW SHOWERS YESTERDAY AFT...GIVEN STEEP LOW LVL LAPSE RATES. THIS WILL BE THE CASE THE NEXT SEVERAL DAYS. A SHOWER WILL BE POSSIBLE AT BFD AND JST BEFORE 12Z TUE AM...BUT STILL THINK THE FIRST PART OF TUESDAY WILL BE MAINLY DRY IN MOST LOCATIONS. OUTLOOK... TUE-WED...SHRA/TSRA. LOCAL RESTRICTIONS LIKELY. THU-FRI...VFR. PERHAPS A SHOWER OR STORM LATE FRI. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...GRUMM SHORT TERM...GRUMM/LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
718 AM EDT MON JUN 23 2014 .SYNOPSIS... A MOISTENING SOUTHERLY FLOW WILL DEVELOP AHEAD OF A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST. THE COLD FRONT WILL PUSH THROUGH THE STATE ON WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR LATE IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... OTHER THAN FOR PATCHY FOG...THE DAY WILL DAWN BRIGHT WITH JUST SOME THIN HIGH CLOUDS BLEEDING ACROSS FROM DYING CONVECTION OVER THE GR LAKES. WITH HIGH PRESSURE NOSING DOWN FROM THE NEW ENGLAND COAST ALL THE WAY TO THE CAROLINAS...SOUTHERLY FLOW ON THE RETURN SIDE WILL BRING STEADILY HIGHER DEWPOINTS NORTHWARD INTO THE REGION OVER THE NEXT COUPLE OF DAYS. AS WE HEAT UP TODAY...WE WILL SEE A STEADY EROSION OF THE STABILITY WITH THE RAP INDICATING MID LEVEL LAPSE RATES EXCEEDING 7C/KM BY EARLY AFTERNOON. HOWEVER CAPE IS EXPECTED TO BE LIMITED BY MID LEVEL DRY AIR OVER CENTRAL AND EASTERN AREAS...WITH THE BEST CHANCE OF POPPING A SHOWER OR STORM BEING OVER MY WESTERN ZONES. MOISTURE WILL BE A BIT DEEPER THERE...BUT EVEN SO A FAIRLY STRONG CAPPING INVERSION WILL BE HARD TO BREAK SO ACTIVITY SHOULD NOT BE WIDESPREAD. HIGHS TODAY LOOK TO BE PRETTY WELL CLUSTERED FROM THE UPPER 70S TO MID 80S...STARTING TO EDGE ABOVE NORMAL FOR A CHANGE. THE PROXIMITY OF THE WAVY FRONT ENTERING THE OHIO VALLEY TONIGHT WILL KEEP A SMALL CHANCE OF SHOWERS AND STORMS LINGERING OVER MY WESTERN AND NORTHWESTERN AREAS OVERNIGHT. IT WILL BE A MILD NIGHT IN THE 60S. && .SHORT TERM /TUESDAY/... TUESDAY WILL BE WARM AND MUGGY WITH AN INCREASING THREAT FOR CONVECTION THE DEEPER INTO THE DAY WE GET. SREF/GEFS BOTH BRING A SURGE OF ANOMALOUSLY HIGH PWATS WITH CAPES EXPECTED EXPECTED TO EXCEED 1000J OVER A WIDE AREA. SPC HAS PLACED US IN A SEE TEXT AREA MENTIONING...STEEP LOW-LEVEL LAPSE RATES MAY BE ENOUGH FOR MARGINALLY SEVERE WIND GUSTS ASSOCIATED WITH SHORT BOWING LINE SEGMENTS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE FRONTAL SYSTEM APPROACHING FROM THE MID WEST IS FORECAST TO BE RATHER WAVY AND COMPLEX...WITH THE POTENTIAL FOR IT TO LINGER OVER THE REGION LONGER THAN PREVIOUSLY INDICATED. BOTH THE GFS AND ECMWF SHOW A NEW WAVE FORMING OVER THE STATE WEDNESDAY...AT LEAST SUPPORTING THE IDEA OF KEEPING HIGH POPS IN THE FORECAST THROUGH THE DAY...BUT ALSO RAISING THE POSSIBILITY OF LOCALLY HEAVY RAINS FOCUSING ALONG THE SLOW MOVING FRONTAL BOUNDARY. DRIER AIR FINALLY LOOKS LIKE IT WILL MAKE A RETURN FOR THURSDAY- FRIDAY AS HIGH PRESSURE BUILDS ACROSS SOUTHERN CANADA JUST NORTH OF THE GREAT LAKES. THE COOL PUSH DOESN`T LOOK TERRIBLY ROBUST SO HIGHS SHOULD REMAIN CLOSE TO OR EVEN A BIT ABOVE NORMAL INTO NEXT WEEKEND. OPERATIONAL GFS/ECMWF DIFFER ON EVENTS FOR SATURDAY-SUNDAY TIMEFRAME WITH THE EXPECTED HANGING AROUND OF THE BOUNDARY THAT IS EXPECTED TO PASS ON WEDNESDAY. THE GFS CREATES QUITE A BIT OF PRECIP FOCUSED ON THE STRONG LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONTAL ZONE. THE ECMWF IS LESS EXCITED ABOUT THIS...KEEPING THE BOUNDARY WEAKER AND FURTHER SOUTH. I DIDN`T BITE TOO HARD ON THE MORE PESSIMISTIC GFS/GEFS...KEEPING JUST SMALL CHANCES OF PRECIP OVER THE NEXT WEEKEND. WORTH NOTING...LAST NIGHT THE LONGER RANGE GUIDANCE WANTED TO REALLY PUMP UP HEIGHTS OVER THE EASTERN US FOR EARLY NEXT WEEK. THE ECMWF HAS DONE A TOTAL FLIP-FLOP ON THIS NOW BRINGING AN UPPER LOW SLOWLY DOWN THE NEW ENGLAND COAST TO OFF NJ BY MONDAY...WITH UPPER HEIGHTS NOT NEARLY AS HIGH AS WAS ADVERTISED. THE GEFS SHOWS MORE RIDGING...BUT SIMILARLY SEEMS TO WANT TO BACK OFF THE IDEA OF A BIG SURGE IN THE SUBTROPICAL RIDGE IN THE EAST. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... HAD FOG FOR A SHORT TIME AT UNV. NOW AT LNS. OTHERWISE...MAINLY LOOKING A DRY DAY TODAY WITH VFR CONDITIONS. ENJOY...AS AT LEAST THE LATER PART OF TUESDAY INTO WED...WILL FEATURE SHOWERS AND THUNDERSTORMS...AS A SW FLOW OF MORE HUMID AIR WORKS IN...AHEAD OF A COLD FRONT FOR LATE WED. THERE WAS A FEW SHOWERS YESTERDAY AFT...GIVEN STEEP LOW LVL LAPSE RATES. THIS WILL BE THE CASE THE NEXT SEVERAL DAYS. A SHOWER WILL BE POSSIBLE AT BFD AND JST BEFORE 12Z TUE AM...BUT STILL THINK THE FIRST PART OF TUESDAY WILL BE MAINLY DRY IN MOST LOCATIONS. OUTLOOK... TUE-WED...SHRA/TSRA. LOCAL RESTRICTIONS LIKELY. THU-FRI...VFR. PERHAPS A SHOWER OR STORM LATE FRI. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
930 AM CDT MON JUN 23 2014 .UPDATE... SEE MORNING UPDATE. && .DISCUSSION... A STRONG OUTFLOW BOUNDARY IS HEADING SOUTH AND CONVECTION IS GETTING CLOSE TO THE NORTHERN PART OF THE CWA. SHORT TERM GUIDANCE STILL SUGGESTS WEAKENING OF THIS SYSTEM BUT THE RAP 13 AND TEXAS TECH 3 KM BECOMING MORE BULLISH WITH POPS OVER THE NW THIRD OF THE CWA. RAISED POPS TO CHANCE OVER THE NW ZONES. 12Z CRP SOUNDING HAS A PW VALUE OF 2.06 INCHES WITH SOME DRY AIR AT 700 MB. THE CONVECTIVE TEMPS ARE IN THE MID 80S WHICH IS MORE THAN REACHABLE. SHORT TERM GUIDANCE SUGGESTS CONVECTION WILL WANE THIS AFTN AS SOME OF THE DRIER AIR ALOFT MIXES TO THE SURFACE. WILL RE-EVALUATE THAT TREND AFTER 17Z. 43 && .PREV DISCUSSION... /ISSUED 648 AM CDT MON JUN 23 2014/ DISCUSSION... UPDATED AVIATION SECTION. AVIATION... LATEST RADAR COMPOSITES SHOW BAND OF STORMS SITUATED OVER NORTH TEXAS...NEAR THE DFW METROPLEX. LINE OF STORMS WAS MOVING SOUTHEAST AROUND 45 MPH. INFRARED SATELLITE SHOWING WARMING CLOUD TOPS AND OVERALL WEAKENING OF THIS CONVECTIVE COMPLEX. AVAILABLE MESO MODELS ARE NOT HANDLING THIS SYSTEM VERY WELL...BUT THESE ALSO SHOW A DISSIPATION OF THE LINE GOING FORWARD. TAFS ARE WRITTEN WITH THE IDEA THAT THIS DISSIPATING TREND WILL CONTINUE...BUT NOT COMPLETELY CERTAIN IT WILL OCCUR GIVEN FAIRLY UNSTABLE AIRMASS DOWNSTREAM. FOR THIS REASON HAVE GONE WITH A VCTS FOR CLL...UTS AND CXO BASED ON TIMING OF CURRENT LINE BUT BASED ON LOW PROBABILITY IT WILL SURVIVE AS A LINE. FARTHER SOUTH AND EAST...EVEN LESS LIKELY LINE WILL MAKE IT...AND WILL CONTINUE WITH NO MENTION OF PRECIP THERE IN THE TAFS. OTHERWISE EXPECT A DECREASE IN CONVECTION TONIGHT...WITH JUST SOME PATCHY MVFR LATE TONIGHT FOR IAH ON NORTH AND NORTHWEST. PREV DISCUSSION... /ISSUED 415 AM CDT MON JUN 23 2014/ DISCUSSION... REGIONAL SATELLITE IMAGERY AND RADAR SHOW MATURE SQUALL LINE PUSHING THROUGH OK/TX AND RED RIVER REGION. CLOSER TO HOUSTON MAINLY OBSERVING SPOTTY SHOWERS BUT NOT MUCH PRECIP HITTING THE GROUND. SQUALL LINE SHOULD CONTINUE TO PUSH SOUTH TOWARDS THE AREA THIS MORNING WITH STRONG COLD POOL BEHIND IT. RAPID REFRESH AND WRF RUNS SHOW THE SQUALL LINE BREAKING UP BEFORE REACHING COLLEGE STATION. KEPT THE FORECAST IN LINE WITH THIS THINKING FOR THE MORNING BUT CONCERNED LINE COULD PUSH FARTHER SOUTH THAN EXPECTED SINCE THERE IS LITTLE SUBSIDENCE AND DRY AIR TO IMPEDE ITS PROGRESS. FORECAST HOLDS WITH 20 POPS AS STILL POSSIBLE FOR ISO CONVECTION TO DEVELOP DURING THE HEAT OF THE DAY. WATER VAPOR IMAGERY AND 00Z 500MB ANALYSIS SHOW TROUGHING OVER MUCH OF TX. UPPER RIDGE IS NOT ALL THAT STRONG AND LIKELY SPLIT BETWEEN NORTHERN MEXICO AND THE C GULF. GLOBAL MODELS ALL SUPPORT TROUGHING OVER TX THROUGH THE END OF THE WEEK. MODELS ALSO SHOW A SURGE IN TROPICAL MOISTURE LATE TUE INTO WED. GIVEN PERCIP WATER VALUES OF NEAR 2 INCHES ACROSS MUCH OF THE AREA FOR WED/THUR DECIDED TO GO WITH 50/60 POPS EACH OF THOSE DAYS. TROPICAL MOISTURE WILL BE SUPPORTIVE OF 1-2 INCH AN HOUR RAINRATES IN STRONGER STORMS SO LOCALLY HEAVY RAINFALL A CONCERN. THIS COULD RESULT IN URBAN FLOODING AND RAPID INCREASES IN BAYOUS. AREAWIDE RAINFALL TOTALS OF 1 TO 2 INCHES OF RAIN WILL BE POSSIBLE FOR THE LATER HALF OF THE WEEK. THE TRICK TO THE FORECAST WILL BE WHERE THE ISOLATED 3 TO 5 INCH RAINFALL AMOUNTS SET UP WHICH COULD LEAD TO FLOODING IMPACTS. UPPER LEVEL RIDGING DOES TRY TO STRENGTHEN DEPENDING ON THE MODEL. THE ECMWF SEEMS TO BE MORE ROBUST WITH THE RIDGE SUNDAY INTO NEXT MONDAY. MEANWHILE THE GFS MAINTAINS A SHEAR AXIS OVER THE NW GULF. RIGHT NOW WILL STILL CARRY SOME LOWER POPS. THINK FRI/SAT WILL BE DRIER BUT 40 POPS STILL DECENT CHANCES. WILL ALSO KEEP 20 POPS IN THE FORECAST FOR SUN/MON AS THERE STILL SHOULD BE PLENTY OF DEEP MOISTURE IN PLACE AND RIDGING STRENGTH WILL STILL BE RELATIVELY UNKNOWN. TEMPERATURES SHOULD REMAIN NEAR NORMAL FOR THE COMING WEEK MAYBE A DEGREE OR TWO COOLER WITH THUNDERSTORM CHANCES. THIS MEANS UPPER 80S TO LOW 90S WITH MIN TEMPS IN THE MID 70S. STILL COULD GET SOME RAIN COOLED LOW 70S OR UPPER 60S BUT DIFFICULT TO FORECAST THOSE OCCURRENCES SINCE IT WILL DEPEND ON THE CONVECTION. THE NICE THING ABOUT THIS FORECAST IS THAT TEMPS SHOULD REMAIN BELOW 95F THROUGH ALMOST THE END OF JUNE. CLIMATE FACTOID...CLL/IAH/HOU HAVE YET TO REACH 95F OR HIGHER THIS YEAR FOR A MAX TEMP. 39 MARINE... LIGHT TO MODERATE ONSHORE FLOW WILL CONTINUE THE NEXT FEW DAYS WITH SUSTAINED 10 METER WINDS GENERALLY ONSHORE AROUND 10 TO 15 KNOTS THROUGH TUESDAY. GRADIENT IS FORECAST TO TIGHTEN SOMEWHAT MID TO LATE WEEK WITH SMALL CRAFT EXERCISE CAUTION WINDS A POSSIBILITY BY WED OR THU. WITH PERSISTENT SE FLOW AND LONG FETCH SEAS ARE EXPECTED TO GRADUALLY BUILD THROUGH THE WEEK...WITH 6 TO 9 FOOT SEAS A GOOD BET BY THURSDAY AND FRIDAY. 46 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 93 74 90 74 88 / 50 20 40 20 60 HOUSTON (IAH) 92 76 90 75 88 / 30 20 40 20 60 GALVESTON (GLS) 89 80 88 80 87 / 20 20 30 40 50 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...43
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
655 AM CDT MON JUN 23 2014 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 308 AM CDT MON JUN 23 2014 MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES TODAY AND THEN AGAIN FROM TUESDAY INTO WEDNESDAY. SURFACE ANALYSIS THIS MORNING SHOWS A VERY WEAK AND ILL DEFINED PATTERN ACROSS THE UPPER MIDWEST. THERE IS A WEAK BOUNDARY WORKING EAST ACROSS MINNESOTA WHERE THE WINDS SWITCH AROUND TO THE WEST AND DEW POINTS BEGIN TO SLOWLY DECREASE. IT APPEARS THE FLOW ABOVE THE SURFACE IS COMING AROUND TO THE WEST/NORTHWEST AHEAD OF THE SURFACE BOUNDARY WITH 925 MB VWP WINDS FROM KDMX AND KMPX ALREADY AROUND TO THE WEST/NORTHWEST. THE 23.00Z NAM AND GFS ALONG WITH THE 23.06Z RAP ALL TRY TO GENERATE A WEAK SURFACE WAVE OVER MISSOURI AND MOVE IT NORTHEAST THIS MORNING INTO EASTERN WISCONSIN ALONG THE LOW LEVEL WIND SHIFT BOUNDARY DEPICTED BY THE VWP WINDS. THE LOW LEVEL MOISTURE CONVERGENCE MAY INCREASE FOR A SHORT WHILE THIS MORNING ON THE NORTHWEST SIDE OF THIS LOW TO POSSIBLY HELP GENERATE A FEW SHOWERS ACROSS THE EASTERN PART OF THE FORECAST AREA. WILL CARRY SOME LOW RAIN CHANCES ACROSS THE EAST TO COVER THIS POSSIBILITY THROUGH ABOUT THE MIDDLE OF THE AFTERNOON. THE NEXT CHANCE OF RAIN WILL THEN COME TUESDAY AS A SHORT WAVE TROUGH DROPS OUT OF SOUTHERN CANADA INTO THE UPPER MIDWEST. THIS WAVE DOES NOT LOOK TO BE VERY STRONG BUT SHOULD STILL BRING SOME WEAK PV ADVECTION IN THE 500-300 MB LAYER ACROSS NORTHERN MINNESOTA AND WISCONSIN. ONLY WEAK MOISTURE CONVERGENCE ALONG THE FRONT AND WITH BETWEEN 500 AND 1000 J/KG OF ML CAPE...IT SHOULD BE ENOUGH TO GENERATE SOME SCATTERED ACTIVITY WITH THE BULK OF THIS OCCURRING IN THE AFTERNOON. WITH THIS BOUNDARY STILL IN THE AREA TUESDAY NIGHT...SOME OF THIS ACTIVITY COULD PERSIST PAST DARK NORTHEAST OF THE I94 CORRIDOR WITH THE COVERAGE DIMINISHING AS THE CAPE DECREASES. ANOTHER SHORT WAVE TROUGH IS EXPECTED TO APPROACH FROM THE WEST WEDNESDAY. THE WEAK PV ADVECTION FROM THIS WAVE SHOULD ONLY ADVANCE INTO WESTERN MINNESOTA AND IOWA BY LATE IN THE DAY. HOWEVER...THE WARM AIR ADVECTION AHEAD OF THIS WAVE SHOULD ALLOW 1-3 UBAR/S OF ISENTROPIC UP GLIDE ON THE 300K SURFACE TO START SPREADING IN THROUGH THE DAY AND THIS COULD AGAIN BE ENOUGH TO GENERATE SOME SCATTERED ACTIVITY AS THE ML CAPE INCREASES TO 500-1000 J/KG. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 308 AM CDT MON JUN 23 2014 THE LONGER RANGE MODELS REMAIN CONSISTENT IN SHOWING A TEMPORARY CHANGE IN THE UPPER AIR FLOW AS A LONG WAVE TROUGH DIGS IN OVER THE INTERMOUNTAIN WEST EARLY IN THIS PERIOD. HOWEVER...THE LATEST TRENDS ARE FOR THIS TROUGH TO NOT BE A FAR SOUTH AS THEY NOW INDICATE AN UPPER LEVEL LOW FORMING OVER CENTRAL CANADA OVER THE WEEKEND. THIS ALLOWS A SOUTHWEST FLOW ALOFT TO REMAIN OVER THE UPPER MIDWEST TO CLOSE OUT THE WEEK AND THEN THE LONG WAVE TROUGH SWINGS THROUGH WITH A POSITIVE TILT TO IT. AT THE SURFACE...HIGH PRESSURE SHOULD BE SOUTH OF HUDSONS BAY TO HELP FUNNEL MOISTURE BACK INTO THE UPPER MIDWEST. THE COMBINATION OF THIS MOISTURE FEED AND SHORT WAVE TROUGHS IN THE SOUTHWEST FLOW AND THEN THE LONG WAVE TROUGH ITSELF WILL KEEP THE RAIN CHANCES GOING THROUGH THE PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 655 AM CDT MON JUN 23 2014 LIFR CONDITIONS IN DENSE FOG WILL OCCUR AT KRST THROUGH 13Z THEN A GRADUAL IMPROVEMENT IS EXPECTED THROUGH 14Z AS MIXING INCREASES. LOW STRATUS WILL PERSIST AT KLSE THROUGH 14Z WITH CEILINGS AT 600 FT. CLOUD BASES WILL GRADUALLY INCREASE THIS MORNING AND THE OVERCAST SHOULD BECOME MORE BROKEN THROUGH THE MID MORNING HOURS. VFR CONDITIONS ARE EXPECTED BY 15Z WITH BROKEN TO SCATTERED CUMULUS. A FEW RAIN SHOWERS AND POSSIBLE TODAY AT THE TAF SITE BUT THEY ARE NOT EXPECTED TO CAUSE SIGNIFICANT VISIBILITY RESTRICTIONS. VFR CONDITIONS ARE EXPECTED LATE THIS AFTERNOON INTO THE OVERNIGHT HOURS AS WEAK HIGH PRESSURE BUILDS IN. && .HYDROLOGY... ISSUED AT 308 AM CDT MON JUN 23 2014 RIVER FLOOD WARNINGS HAVE BEEN PAIRED BACK TO ALMOST JUST THE MISSISSIPPI RIVER. GIVEN THAT ADDITIONAL HEAVY RAIN DID NOT FALL AND IS NOT EXPECTED OVER THE NEXT SEVERAL DAYS...THE FLOODING WILL BECOME CONFINED TO JUST THE MISSISSIPPI. MANY LOCATIONS ALONG THE MISSISSIPPI ARE EXPECTED TO BE NEAR OR ABOVE FLOOD STAGE THROUGH THE WEEK. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...WETENKAMP HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS TUCSON AZ
245 PM MST MON JUN 23 2014 .SYNOPSIS...A FEW SHOWERS AND THUNDERSTORMS WILL OCCUR ACROSS FAR SOUTHEASTERN SECTIONS EARLY THIS EVENING. OTHERWISE...DRY CONDITIONS WILL PREVAIL INTO EARLY NEXT WEEK. DAYTIME TEMPERATURES WILL BE NEAR TO A FEW DEGREES ABOVE AVERAGE THIS WEEK FOLLOWED BY EVEN HOTTER TEMPERATURES BY EARLY NEXT WEEK. && .DISCUSSION...KEMX WSR-88D DETECTED ISOLATED 30-45 DBZ ECHOES IN THE VICINITY OF THE CHIRICAHUA MOUNTAINS IN ERN COCHISE COUNTY AT 2140Z. SOME LIGHTNING STRIKES WERE DETECTED JUST EAST OF THE CHIRICAHUA MTNS NEAR THE NEW MEXICO BORDER. OTHERWISE...CLEAR SKIES PREVAILED ACROSS MUCH OF PIMA/SRN PINAL COUNTIES...AND SCATTERED CUMULOFORM CLOUDS WERE MOSTLY EAST AND SOUTH OF TUCSON. 23/19Z HRRR WAS SIMILAR TO PREVIOUS SOLUTIONS IN DEPICTING WEAK PRECIP ECHOES TO OCCUR ACROSS ABOUT THE ERN HALF OF COCHISE COUNTY THRU ABOUT 24/03Z. BELIEVE THERE IS JUST ENOUGH LOWER AND MID-LEVEL MOISTURE TO MAINTAIN A SLIGHT CHANCE OF SHOWERS/TSTMS ACROSS THE CHIRICAHUA MOUNTAINS EARLY THIS EVENING. VERY LITTLE RAINFALL IS EXPECTED FROM THIS ACTIVITY. THE NEAR-SURFACE ENVIRONMENT IS TOO DRY TO SUPPORT THE DEPICTION/MENTION OF MEASURABLE PRECIP AT LOWER ELEVATIONS OF COCHISE COUNTY. THEREAFTER...CLEAR SKIES OR MOSTLY CLEAR SKIES WILL PREVAIL LATER THIS EVENING AND THE REST OF TONIGHT. HIGH PRESSURE ALOFT CENTERED WEST OF NRN BAJA CALIFORNIA GENERALLY NEAR 28N/128W WITH RIDGE AXIS EXTENDING EWD ACROSS SONORA MEXICO WILL REMAIN QUASI-STATIONARY THRU WED. THIS PATTERN WILL PRODUCE CLEAR SKIES OR MOSTLY CLEAR SKIES...WITH ANY THUNDERSTORMS EXPECTED TO REMAIN SE OF THE AREA ACROSS NERN SONORA/NWRN CHIHUAHUA. A LOW PRESSURE TROUGH WILL ENTER THE PACIFIC NW WED NIGHT. THIS SYSTEM IS THEN PROGGED TO MOVE SEWD ACROSS THE GREAT BASIN THUR...AND CONTINUE EWD INTO THE NRN/CENTRAL ROCKIES FRI. THE 23/12Z GFS/ECMWF/CANADIAN WERE IN DECENT AGREEMENT WITH THIS SYSTEM. THERE MAY BE SOME ENHANCED WIND SPEEDS FRI AFTERNOON...PARTICULARLY IN THE SAFFORD VALLEY GIVEN THE ORIENTATION OF THE MID-LEVEL GRADIENT. HOWEVER...WIND SPEEDS AT THIS TIME ARE PROJECTED TO REMAIN WELL BELOW WIND ADVISORY CRITERIA. A VERY DRY REGIME WILL THEN CONTINUE SAT UNDER LIGHT WLY/NWLY FLOW ALOFT. THEREAFTER...GFS/ECMWF WERE SIMILAR WITH DEPICTING A BROAD AREA OF HIGH PRESSURE ALOFT EXTENDING FROM THE ERN PACIFIC EWD INTO TEXAS SUN. HIGH PRESSURE ALOFT IS THEN PROGGED TO BECOME CENTERED ESSENTIALLY OVER NWRN NEW MEXICO MON. THIS PATTERN YIELDED A LIGHT GENERALLY ELY MID-LEVEL FLOW REGIME ACROSS SE AZ. HOWEVER...BOTH MODELS DEPICTED PRECIP-FREE CONDITIONS ACROSS THIS FORECAST AREA...WITH ANY MEASURABLE PRECIP WELL EAST TO SOUTHEAST FROM ERN NEW MEXICO INTO EAST CENTRAL SONORA. THUS...FOR THIS FORECAST PACKAGE...HAVE MAINTAINED DRY CONDITIONS NEXT MON. HOWEVER...THE ECMWF THEN PRODUCED FAIRLY ROBUST QPF/S JUST EAST TO SOUTHEAST OF THE AREA NEXT TUE (JULY 1) FOLLOWED BY MEASURABLE PRECIP ACROSS MUCH OF THE AREA NEXT WED (JULY 2). THESE DAYS ARE BEYOND THE SCOPE OF THIS FORECAST PACKAGE. AT ANY RATE...THE SYNOPTIC SCALE PATTERN APPEARS TO BE BECOMING MORE CONDUCIVE FOR THE DEEPER IMPORT OF MOISTURE INTO SE AZ BY ABOUT THE MIDDLE OF NEXT WEEK...AT LEAST FROM A MEDIUM RANGE MODEL PERSPECTIVE. HIGH TEMPS TUE-SAT WILL BE AT NORMAL VALUES OR AVERAGE JUST A FEW DEGS ABOVE SEASONAL NORMALS. NO COOLING OF SIGNIFICANCE IS EXPECTED FRI AS PREVIOUSLY THOUGHT. THEREAFTER...WARMER TEMPERATURES ARE FORECAST TO OCCUR SUN-MON DUE TO INCREASED HEIGHTS/THICKNESSES IN RESPONSE TO THE AMPLIFICATION OF THE UPPER RIDGE ACROSS THE AREA. && .AVIATION...VALID THRU 25/00Z. ISOLATED THUNDERSTORMS WILL OCCUR MAINLY EAST OF A WILLCOX TO KDUG LINE IN THE ERN HALF OF COCHISE COUNTY EARLY THIS EVENING. OTHERWISE...A FEW TO SCATTERED CLOUDS GENERALLY AT 10-15K FT AGL INTO THIS EVENING AND AGAIN TUESDAY AFTERNOON. EXPECT CLEAR SKIES ACROSS MUCH OF THE AREA LATE TONIGHT AND TUESDAY MORNING. SURFACE WINDS INTO THIS EVENING AND TUESDAY AFTERNOON WILL BE SWLY TO NWLY AT 12-18 KTS WITH GUSTS TO NEAR 25 KTS. OTHERWISE...SURFACE WINDS WILL BE LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A FEW SHOWERS AND THUNDERSTORMS PRODUCING VERY LITTLE RAINFALL WILL OCCUR ACROSS ABOUT THE EASTERN HALF OF COCHISE COUNTY EARLY THIS EVENING. OTHERWISE...DRY CONDITIONS WILL PREVAIL INTO EARLY NEXT WEEK. NORMAL DIURNAL WIND TRENDS WILL OCCUR THROUGH MUCH OF THE FORECAST PERIOD...WITH OCCASIONAL GUSTS DURING THE AFTERNOON AND EARLY EVENING HOURS DUE TO DAYTIME HEATING. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS
AREA FORECAST DISCUSSION
NWS TUCSON AZ
240 PM MST MON JUN 23 2014 .SYNOPSIS...A FEW SHOWERS AND THUNDERSTORMS WILL OCCUR ACROSS FAR SOUTHEASTERN SECTIONS EARLY THIS EVENING. OTHERWISE...DRY CONDITIONS WILL PREVAIL INTO EARLY NEXT WEEK. DAYTIME TEMPERATURES WILL BE NEAR TO A FEW DEGREES ABOVE AVERAGE THIS WEEK FOLLOWED BY EVEN HOTTER TEMPERATURES BY EARLY NEXT WEEK. && .DISCUSSION...KEMX WSR-88D DETECTED ISOLATED 30-35 DBZ ECHOES NEAR THE CHIRICAHUA MOUNTAINS IN ERN COCHISE COUNTY AT 2115Z. OTHERWISE... CLEAR SKIES PREVAILED ACROSS MUCH OF PIMA/SRN PINAL COUNTIES...AND SCATTERED CUMULOFORM CLOUDS WERE MOSTLY EAST AND SOUTH OF TUCSON. 23/19Z HRRR WAS SIMILAR TO PREVIOUS SOLUTIONS IN DEPICTING WEAK PRECIP ECHOES TO OCCUR ACROSS ABOUT THE ERN HALF OF COCHISE COUNTY THRU ABOUT 24/03Z. BELIEVE THERE IS JUST ENOUGH LOWER AND MID-LEVEL MOISTURE TO MAINTAIN A SLIGHT CHANCE OF SHOWERS/TSTMS ACROSS THE CHIRICAHUA MOUNTAINS EARLY THIS EVENING. VERY LITTLE RAINFALL IS EXPECTED FROM THIS ACTIVITY. THE NEAR-SURFACE ENVIRONMENT IS TOO DRY TO SUPPORT THE DEPICTION/MENTION OF SHOWERS/TSTMS AT LOWER ELEVATIONS OF COCHISE COUNTY. THEREAFTER...CLEAR SKIES OR MOSTLY CLEAR SKIES WILL PREVAIL LATER THIS EVENING AND THE REST OF TONIGHT. HIGH PRESSURE ALOFT CENTERED WEST OF NRN BAJA CALIFORNIA GENERALLY NEAR 28N/128W WITH RIDGE AXIS EXTENDING EWD ACROSS SONORA MEXICO WILL REMAIN QUASI-STATIONARY THRU WED. THIS PATTERN WILL PRODUCE CLEAR SKIES OR MOSTLY CLEAR SKIES...WITH ANY THUNDERSTORMS EXPECTED TO REMAIN SE OF THE AREA ACROSS NERN SONORA/NWRN CHIHUAHUA. A LOW PRESSURE TROUGH WILL ENTER THE PACIFIC NW WED NIGHT. THIS SYSTEM IS THEN PROGGED TO MOVE SEWD ACROSS THE GREAT BASIN THUR...AND CONTINUE EWD INTO THE NRN/CENTRAL ROCKIES FRI. THE 23/12Z GFS/ECMWF/CANADIAN WERE IN DECENT AGREEMENT WITH THIS SYSTEM. THERE MAY BE SOME ENHANCED WIND SPEEDS FRI AFTERNOON...PARTICULARLY IN THE SAFFORD VALLEY GIVEN THE ORIENTATION OF THE MID-LEVEL GRADIENT. HOWEVER...WIND SPEEDS AT THIS TIME ARE PROJECTED TO REMAIN WELL BELOW WIND ADVISORY CRITERIA. A VERY DRY REGIME WILL THEN CONTINUE SAT UNDER LIGHT WLY/NWLY FLOW ALOFT. THEREAFTER...GFS/ECMWF WERE SIMILAR WITH DEPICTING A BROAD AREA OF HIGH PRESSURE ALOFT EXTENDING FROM THE ERN PACIFIC EWD INTO TEXAS SUN. HIGH PRESSURE ALOFT IS THEN PROGGED TO BECOME CENTERED ESSENTIALLY OVER NWRN NEW MEXICO MON. THIS PATTERN YIELDED A LIGHT GENERALLY ELY MID-LEVEL FLOW REGIME ACROSS SE AZ. HOWEVER...BOTH MODELS DEPICTED PRECIP-FREE CONDITIONS ACROSS THIS FORECAST AREA...WITH ANY MEASURABLE PRECIP WELL EAST TO SOUTHEAST FROM ERN NEW MEXICO INTO EAST CENTRAL SONORA. THUS...FOR THIS FORECAST PACKAGE...HAVE MAINTAINED DRY CONDITIONS NEXT MON. HOWEVER...THE ECMWF THEN PRODUCED FAIRLY ROBUST QPF/S JUST EAST TO SOUTHEAST OF THE AREA NEXT TUE (JULY 1) FOLLOWED BY MEASURABLE PRECIP ACROSS MUCH OF THE AREA NEXT WED (JULY 2). THESE DAYS ARE BEYOND THE SCOPE OF THIS FORECAST PACKAGE. AT ANY RATE...THE SYNOPTIC SCALE PATTERN APPEARS TO BE BECOMING MORE CONDUCIVE FOR THE DEEPER IMPORT OF MOISTURE INTO SE AZ BY ABOUT THE MIDDLE OF NEXT WEEK...AT LEAST FROM A MEDIUM RANGE MODEL PERSPECTIVE. HIGH TEMPS TUE-SAT WILL BE AT NORMAL VALUES OR AVERAGE JUST A FEW DEGS ABOVE SEASONAL NORMALS. NO COOLING OF SIGNIFICANCE IS EXPECTED FRI AS PREVIOUSLY THOUGHT. THEREAFTER...WARMER TEMPERATURES ARE FORECAST TO OCCUR SUN-MON DUE TO INCREASED HEIGHTS/THICKNESSES IN RESPONSE TO THE AMPLIFICATION OF THE UPPER RIDGE ACROSS THE AREA. && .AVIATION...VALID THRU 25/00Z. ISOLATED THUNDERSTORMS WILL OCCUR MAINLY EAST OF A WILLCOX TO KDUG LINE IN THE ERN HALF OF COCHISE COUNTY EARLY THIS EVENING. OTHERWISE...A FEW TO SCATTERED CLOUDS GENERALLY AT 10-15K FT AGL INTO THIS EVENING AND AGAIN TUESDAY AFTERNOON. EXPECT CLEAR SKIES ACROSS MUCH OF THE AREA LATE TONIGHT AND TUESDAY MORNING. SURFACE WINDS INTO THIS EVENING AND TUESDAY AFTERNOON WILL BE SWLY TO NWLY AT 12-18 KTS WITH GUSTS TO NEAR 25 KTS. OTHERWISE...SURFACE WINDS WILL BE LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A FEW SHOWERS AND THUNDERSTORMS PRODUCING VERY LITTLE RAINFALL WILL OCCUR ACROSS ABOUT THE EASTERN HALF OF COCHISE COUNTY EARLY THIS EVENING. OTHERWISE...DRY CONDITIONS WILL PREVAIL INTO EARLY NEXT WEEK. NORMAL DIURNAL WIND TRENDS WILL OCCUR THROUGH MUCH OF THE FORECAST PERIOD...WITH OCCASIONAL GUSTS DURING THE AFTERNOON AND EARLY EVENING HOURS DUE TO DAYTIME HEATING. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
256 PM CDT MON JUN 23 2014 .DISCUSSION... 1147 AM CDT STILL EXPECTING AN INCREASE IN THE COVERAGE OF SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS THROUGH THE AFTERNOON HOURS. MOST OF THE CONVECTIVE ACTIVITY THIS MORNING WAS LOCATED SOUTHEAST OF THE AREA. THIS WAS IN THE REGION OF BETTER SURFACE HEATING AND HIGHER DEWPOINTS. A BROAD AREA OF MOISTURE CONVERGENCE IS NOW MOVING TOWARD NORTHERN IL AND NORTHWEST INDIANA AS DEPICTED BOTH BY THE LATEST RAP FORECASTS AS WELL AS THE SPC MESOANALYSIS. THIS AFTERNOON...SHOWERS ARE EXPECTED TO DEVELOP IN THIS REGION OF INCREASING MOISTURE...AHEAD OF AN APPROACHING FRONTAL ZONE AND UNDER THE WEAK MID TO UPPER SHORTWAVES SPINNING THROUGH THE UPPER TROUGH. THE RADAR MOSAIC AT THE NOON HOUR WAS STARTING TO HINT AT THIS DEVELOPMENT...AND THE VISIBILE SATELLITE CHANNEL WAS SHOWING SIGNS OF CYCLONIC CIRCULATION THAT WOULD FURTHER ENHANCE CONVERGENCE. MILD AIR ALOFT AND THE LACK OF STRONG WINDS AT UPPER LEVELS ARE RESULTING IN TALL SKINNY SOUNDINGS WITH LITTLE DEEP LAYER SHEAR...SO LOCALLY HEAVY RAIN COULD BE A PROBLEM BUT WIDESPREAD ORGANIZED SEVERE STORMS ARE NOT A LARGE CONCERN. THE MOST FAVORABLE AXIS FOR DEVELOPMENT THEN SHIFTS SOUTH AND EAST OF THE IMMEDIATE CHICAGO METRO AREA BY LATE EVENING. LENNING //PREV DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * INCREASING TSRA COVERAGE SOUTH AND EAST OF THE TERMINALS. MAINLY SHRA WITH ISOLATED TSRA AT THE TERMINALS. * UNCERTAIN WIND DIRECTION...WESTERLY IN THE IMMEDIATE TERM BUT FAVORING SOUTHWESTERLY AHEAD OF AN APPROACHING FRONT...THEN VEERING WESTERLY AGAIN TONIGHT. SPEEDS GENERALLY UNDER 10 KTS. * PATCHY MVFR CIGS BUT TRENDING MOSTLY VFR. MVFR VSBYS IN SHOWERS. LENNING //DISCUSSION...UPDATED 20Z... THUNDERSTORM ACTIVITY HAS INCREASED ACROSS EAST CENTRAL ILLINIOS INTO NORTHWEST INDIANA WHICH IS POSING PROBLEMS FOR INBOUND AND OUTBOUD FLIGHTS...BUT MAINLY JUST SHOWERS WITH ISOLATED TSRA ARE EXPECTED AROUND THE TERMINAL AREAS. CEILINGS HAD LOWERED TO MVFR RANGE BRIEFLY BUT NOW ARE HEADING BACK UP...AND VSBY CONDITIONS GENERALLY ARE EXPECTED TO REMAIN VFR EXCEPT FOR BRIEF PERIODS NEAR THE HEAVIER SHOWERS. THE PEAK COVERAGE STILL IS EXPECTED TOWARD MID TO LATE AFTERNOON...WITH THE BEST FOCUS BEGINNING TO SHIFT EAST BY LATE EVENING. WINDS WILL REMAIN LIGHT OUT OF THE SOUTHWEST AND THEN WEST AS A FRONT CROSSES THE AREA TONIGHT. TUESDAY LOOKS MOSTLY DRY...WITH AN AFTERNOON LAKE BREEZE LIKELY DEVELOPING IN THE LIGHT PRESSURE GRADIENT. LENNING //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM CONFIDENCE IN SHRA COVERAGE...AND MEDIUM TO HIGH CONFIDENCE THAT MOST TSRA STAYS SOUTH AND EAST OF THE TERMINALS. * MEDIUM TO HIGH CONFIDENCE IN VFR CIGS/VSBYS AWAY FROM SHOWERS. * LOW CONFIDENCE IN WIND DIRECTION...BUT HIGHER CONFIDENCE IN SPEEDS. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. THURSDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE TSRA. OTHERWISE VFR. SUNDAY...SLIGHT CHANCE TSRA. OTHERWISE VFR. KREIN && .MARINE... 223 PM CDT WEBCAMS AND SATELLITE IMAGERY BOTH SUGGEST DENSE FOG IS STILL OVER THE LAKE...SO WILL KEEP THE DENSE FOG ADVISORY GOING. THERE IS A LITTLE CONCERN THAT THE FOG MAY CONTINUE THROUGH TONIGHT...BUT DO NOT HAVE ENOUGH CONFIDENCE TO EXTEND THE ADVISORY NOW. A LOW PRESSURE TROUGH AND COLD FRONT WILL MOVE OVER THE LAKE TONIGHT AND WINDS WILL NW TO W BEHIND THE FRONT. THE BAGGY TROUGH REMAINS OVERHEAD TOMORROW AND EXPECTING ONSHORE FLOW DEVELOP ACROSS THE LAKE IN THE AFTERNOON. A SECOND COLD FRONT SINKS DOWN THE LAKE IN THE EVENING WITH WINDS BECOMING NORTH 10-15 KT BEHIND IT. WINDS REMAIN LIGHT OUT OF THE N TO NE AS HIGH PRESSURE BUILDS OVER THE LAKE WEDNESDAY NIGHT. THE LIGHT WINDS THEN VEER TO EAST THURSDAY NIGHT AS THE HIGH SHIFTS EAST. THE GRADIENT TIGHTENS LATE THIS WEEK INTO NEXT WEEK AHEAD OF THE NEXT STORM SYSTEM WITH SOUTH WINDS GUSTING TO AROUND 20 KT SUNDAY. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
224 PM CDT MON JUN 23 2014 .DISCUSSION... 1147 AM CDT STILL EXPECTING AN INCREASE IN THE COVERAGE OF SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS THROUGH THE AFTERNOON HOURS. MOST OF THE CONVECTIVE ACTIVITY THIS MORNING WAS LOCATED SOUTHEAST OF THE AREA. THIS WAS IN THE REGION OF BETTER SURFACE HEATING AND HIGHER DEWPOINTS. A BROAD AREA OF MOISTURE CONVERGENCE IS NOW MOVING TOWARD NORTHERN IL AND NORTHWEST INDIANA AS DEPICTED BOTH BY THE LATEST RAP FORECASTS AS WELL AS THE SPC MESOANALYSIS. THIS AFTERNOON...SHOWERS ARE EXPECTED TO DEVELOP IN THIS REGION OF INCREASING MOISTURE...AHEAD OF AN APPROACHING FRONTAL ZONE AND UNDER THE WEAK MID TO UPPER SHORTWAVES SPINNING THROUGH THE UPPER TROUGH. THE RADAR MOSAIC AT THE NOON HOUR WAS STARTING TO HINT AT THIS DEVELOPMENT...AND THE VISIBILE SATELLITE CHANNEL WAS SHOWING SIGNS OF CYCLONIC CIRCULATION THAT WOULD FURTHER ENHANCE CONVERGENCE. MILD AIR ALOFT AND THE LACK OF STRONG WINDS AT UPPER LEVELS ARE RESULTING IN TALL SKINNY SOUNDINGS WITH LITTLE DEEP LAYER SHEAR...SO LOCALLY HEAVY RAIN COULD BE A PROBLEM BUT WIDESPREAD ORGANIZED SEVERE STORMS ARE NOT A LARGE CONCERN. THE MOST FAVORABLE AXIS FOR DEVELOPMENT THEN SHIFTS SOUTH AND EAST OF THE IMMEDIATE CHICAGO METRO AREA BY LATE EVENING. LENNING //PREV DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * INCREASING COVERAGE OF SHOWERS WITH ISOLATED TSRA THIS AFTERNOON AND EVENING. * SHORT PERIODS OF MVFR VSBYS IN HEAVIER ACTIVITY. * WINDS LIGHT FROM THE SOUTH...GRADUALLY VEERING NORTHWEST. * LAKE BREEZE LIKELY TOMORROW AFTERNOON. LENNING //DISCUSSION...UPDATED 18Z... THUNDERSTORM ACTIVITY INCREASING ACROSS EAST CENTRAL ILLINIOS INTO NORTHWEST INDIANA MAY POSE PROBLEMS FOR INBOUND AND OUTBOUD FLIGHTS...BUT MAINLY JUST SHOWERS WITH ISOLATED TSRA ARE EXPECTED AROUND THE TERMINAL AREAS. CEILINGS LOWERING TO MVFR RANGE MAY PROMPT A TAF AMENDMENT A BIT SOONER THAN EXPECTED...THOUGH VSBY CONDITIONS GENERALLY ARE EXPECTED TO BE VFR EXCEPT FOR BRIEF PERIODS NEAR THE HEAVIER SHOWERS. THE PEAK COVERAGE IS EXPECTED TOWARD MID TO LATE AFTERNOON...WITH THE BEST FOCUS BEGINNING TO SHIFT EAST BY LATE EVENING. WINDS WILL REMAIN LIGHT OUT OF THE SOUTH BEFORE GRADUALLY VEERING SOUTHWEST AND THEN WEST AS A FRONT CROSSES THE AREA TONIGHT. TUESDAY LOOKS MOSTLY DRY...WITH AN AFTERNOON LAKE BREEZE LIKELY DEVELOPING IN THE LIGHT PRESSURE GRADIENT. LENNING //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO LOW CONFIDENCE ON CEILINGS STAYING ABOVE MVFR...BUT HIGHER ON VSBYS STAYING VFR. * MEDIUM TO HIGH CONFIDENCE OF SHOWERS THIS AFTERNOON AND EVENING. * MEDIUM CONFIDENCE ON WIND DIRECTION TRENDS...HIGHER ON SPEED TRENDS. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. THURSDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE TSRA. OTHERWISE VFR. SUNDAY...SLIGHT CHANCE TSRA. OTHERWISE VFR. KREIN && .MARINE... 223 PM CDT WEBCAMS AND SATELLITE IMAGERY BOTH SUGGEST DENSE FOG IS STILL OVER THE LAKE...SO WILL KEEP THE DENSE FOG ADVISORY GOING. THERE IS A LITTLE CONCERN THAT THE FOG MAY CONTINUE THROUGH TONIGHT...BUT DO NOT HAVE ENOUGH CONFIDENCE TO EXTEND THE ADVISORY NOW. A LOW PRESSURE TROUGH AND COLD FRONT WILL MOVE OVER THE LAKE TONIGHT AND WINDS WILL NW TO W BEHIND THE FRONT. THE BAGGY TROUGH REMAINS OVERHEAD TOMORROW AND EXPECTING ONSHORE FLOW DEVELOP ACROSS THE LAKE IN THE AFTERNOON. A SECOND COLD FRONT SINKS DOWN THE LAKE IN THE EVENING WITH WINDS BECOMING NORTH 10-15 KT BEHIND IT. WINDS REMAIN LIGHT OUT OF THE N TO NE AS HIGH PRESSURE BUILDS OVER THE LAKE WEDNESDAY NIGHT. THE LIGHT WINDS THEN VEER TO EAST THURSDAY NIGHT AS THE HIGH SHIFTS EAST. THE GRADIENT TIGHTENS LATE THIS WEEK INTO NEXT WEEK AHEAD OF THE NEXT STORM SYSTEM WITH SOUTH WINDS GUSTING TO AROUND 20 KT SUNDAY. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
115 PM CDT MON JUN 23 2014 .DISCUSSION... 1147 AM CDT STILL EXPECTING AN INCREASE IN THE COVERAGE OF SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS THROUGH THE AFTERNOON HOURS. MOST OF THE CONVECTIVE ACTIVITY THIS MORNING WAS LOCATED SOUTHEAST OF THE AREA. THIS WAS IN THE REGION OF BETTER SURFACE HEATING AND HIGHER DEWPOINTS. A BROAD AREA OF MOISTURE CONVERGENCE IS NOW MOVING TOWARD NORTHERN IL AND NORTHWEST INDIANA AS DEPICTED BOTH BY THE LATEST RAP FORECASTS AS WELL AS THE SPC MESOANALYSIS. THIS AFTERNOON...SHOWERS ARE EXPECTED TO DEVELOP IN THIS REGION OF INCREASING MOISTURE...AHEAD OF AN APPROACHING FRONTAL ZONE AND UNDER THE WEAK MID TO UPPER SHORTWAVES SPINNING THROUGH THE UPPER TROUGH. THE RADAR MOSAIC AT THE NOON HOUR WAS STARTING TO HINT AT THIS DEVELOPMENT...AND THE VISIBILE SATELLITE CHANNEL WAS SHOWING SIGNS OF CYCLONIC CIRCULATION THAT WOULD FURTHER ENHANCE CONVERGENCE. MILD AIR ALOFT AND THE LACK OF STRONG WINDS AT UPPER LEVELS ARE RESULTING IN TALL SKINNY SOUNDINGS WITH LITTLE DEEP LAYER SHEAR...SO LOCALLY HEAVY RAIN COULD BE A PROBLEM BUT WIDESPREAD ORGANIZED SEVERE STORMS ARE NOT A LARGE CONCERN. THE MOST FAVORABLE AXIS FOR DEVELOPMENT THEN SHIFTS SOUTH AND EAST OF THE IMMEDIATE CHICAGO METRO AREA BY LATE EVENING. LENNING //PREV DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * INCREASING COVERAGE OF SHOWERS WITH ISOLATED TSRA THIS AFTERNOON AND EVENING. * SHORT PERIODS OF MVFR VSBYS IN HEAVIER ACTIVITY. * WINDS LIGHT FROM THE SOUTH...GRADUALLY VEERING NORTHWEST. * LAKE BREEZE LIKELY TOMORROW AFTERNOON. LENNING //DISCUSSION...UPDATED 18Z... THUNDERSTORM ACTIVITY INCREASING ACROSS EAST CENTRAL ILLINIOS INTO NORTHWEST INDIANA MAY POSE PROBLEMS FOR INBOUND AND OUTBOUD FLIGHTS...BUT MAINLY JUST SHOWERS WITH ISOLATED TSRA ARE EXPECTED AROUND THE TERMINAL AREAS. CEILINGS LOWERING TO MVFR RANGE MAY PROMPT A TAF AMENDMENT A BIT SOONER THAN EXPECTED...THOUGH VSBY CONDITIONS GENERALLY ARE EXPECTED TO BE VFR EXCEPT FOR BRIEF PERIODS NEAR THE HEAVIER SHOWERS. THE PEAK COVERAGE IS EXPECTED TOWARD MID TO LATE AFTERNOON...WITH THE BEST FOCUS BEGINNING TO SHIFT EAST BY LATE EVENING. WINDS WILL REMAIN LIGHT OUT OF THE SOUTH BEFORE GRADUALLY VEERING SOUTHWEST AND THEN WEST AS A FRONT CROSSES THE AREA TONIGHT. TUESDAY LOOKS MOSTLY DRY...WITH AN AFTERNOON LAKE BREEZE LIKELY DEVELOPING IN THE LIGHT PRESSURE GRADIENT. LENNING //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO LOW CONFIDENCE ON CEILINGS STAYING ABOVE MVFR...BUT HIGHER ON VSBYS STAYING VFR. * MEDIUM TO HIGH CONFIDENCE OF SHOWERS THIS AFTERNOON AND EVENING. * MEDIUM CONFIDENCE ON WIND DIRECTION TRENDS...HIGHER ON SPEED TRENDS. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. THURSDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE TSRA. OTHERWISE VFR. SUNDAY...SLIGHT CHANCE TSRA. OTHERWISE VFR. KREIN && .MARINE... 315 AM CDT BROAD HIGH PRESSURE EXTENDS FROM THE GREAT LAKES REGION ACROSS MUCH OF THE EAST COAST. THE RESULTANT LIGHT AND VARIABLE WINDS COMBINED WITH RESIDUAL HIGH DEWPOINT AIR OVER THE STILL VERY COLD LAKE WATERS HAS KEPT DENSE FOG IN PLACE. THE DENSE FOG WILL CONTINUE WHILE THE HIGH PRESSURE IS SLOWLY ERODED BY A TROUGH OF WEAK LOW PRESSURE AS IT MOVES ACROSS THE MISSISSIPPI VALLEY MONDAY MORNING. THE TROUGH AND AN ASSOCIATED WEAK COLD FRONT WILL MOVE ACROSS THE LAKE LATE MONDAY NIGHT TURNING WINDS FROM LIGHT AND VARIABLE TO WESTERLY AND NORTHWESTERLY...WHICH WILL BEGIN TO SCOUR OUT THE FOG FROM THE LAKE. A SECONDARY COLD FRONT WILL DROP DOWN THE LAKE TUESDAY TURNING WINDS NORTHERLY BRINGING AN END TO ANY RESIDUAL FOG AS DRIER AIR FILTERS OVER THE LAKE. HIGH PRESSURE WILL BUILD ACROSS THE UPPER LAKES WEDNESDAY AND THURSDAY KEEPING CONDITIONS OVER THE LAKE RELATIVELY QUIET...BUT BY THE END OF THE WEEK...STRENGTHENING SOUTHERLY WINDS OF 15 TO 25 KT WILL DEVELOP OVER THE LAKE AS THE HIGH MOVES OFF TO THE EAST AND ANOTHER TROUGH APPROACHES FROM THE WEST. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1213 PM CDT MON JUN 23 2014 .DISCUSSION... 1147 AM CDT STILL EXPECTING AN INCREASE IN THE COVERAGE OF SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS THROUGH THE AFTERNOON HOURS. MOST OF THE CONVECTIVE ACTIVITY THIS MORNING WAS LOCATED SOUTHEAST OF THE AREA. THIS WAS IN THE REGION OF BETTER SURFACE HEATING AND HIGHER DEWPOINTS. A BROAD AREA OF MOISTURE CONVERGENCE IS NOW MOVING TOWARD NORTHERN IL AND NORTHWEST INDIANA AS DEPICTED BOTH BY THE LATEST RAP FORECASTS AS WELL AS THE SPC MESOANALYSIS. THIS AFTERNOON...SHOWERS ARE EXPECTED TO DEVELOP IN THIS REGION OF INCREASING MOISTURE...AHEAD OF AN APPROACHING FRONTAL ZONE AND UNDER THE WEAK MID TO UPPER SHORTWAVES SPINNING THROUGH THE UPPER TROUGH. THE RADAR MOSAIC AT THE NOON HOUR WAS STARTING TO HINT AT THIS DEVELOPMENT...AND THE VISIBILE SATELLITE CHANNEL WAS SHOWING SIGNS OF CYCLONIC CIRCULATION THAT WOULD FURTHER ENHANCE CONVERGENCE. MILD AIR ALOFT AND THE LACK OF STRONG WINDS AT UPPER LEVELS ARE RESULTING IN TALL SKINNY SOUNDINGS WITH LITTLE DEEP LAYER SHEAR...SO LOCALLY HEAVY RAIN COULD BE A PROBLEM BUT WIDESPREAD ORGANIZED SEVERE STORMS ARE NOT A LARGE CONCERN. THE MOST FAVORABLE AXIS FOR DEVELOPMENT THEN SHIFTS SOUTH AND EAST OF THE IMMEDIATE CHICAGO METRO AREA BY LATE EVENING. LENNING && .PREV DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * INCREASING SHRA COVERAGE EXPECTED THROUGH MID AFTERNOON...WITH ISOLATED TSRA. * POSSIBLE MVFR CIGS/VSBYS IN HEAVIER SHOWERS BUT GENERALLY VFR. * VARIABLE WINDS...SOUTHERLY TO SOUTHWESTERLY...VEERING WEST LATE. LENNING //DISCUSSION...UPDATED 12Z... THE PCPN FORECAST REMAINS THE MAIN CONCERN WITH SOME UNCERTAINTY CONTINUING WITH THE TSRA POTENTIAL. THE ENVIRONMENT OVER THE AREA REMAINS VERY MOIST AND SHOULD BECOME AT LEAST WEAKLY UNSTABLE THROUGH THE DAY. A MODERATE SHORTWAVE ALOFT HAS BEEN CONSISTENTLY FORECAST BY THE MODELS TO CROSS THE REGION THIS AFTERNOON...AND WILL BE ACCOMPANIED BY A WEAK COLD FRONT. FRONTAL FORCING WILL BE LOW AS THERE WILL BE ONLY A MINOR AIRMASS CHANGE WITH THE FRONTAL PASSAGE AND A WINDSHIFT FROM LIGHT SOUTHERLY WINDS TO LIGHT NWLY WINDS. THERE MAY BE A FEW GUSTS TO ARND 15KT IN THE WEAK WARM ADVECTION AHEAD OF THE FRONT...BUT WINDS SHOULD BE LESS THAN 10KT BEHIND THE FRONT. THE LATEST GUIDANCE AND SATELLITE TRENDS INDICATE A WEAKER SHORTWAVE ALOFT THAN PREVIOUSLY NOTED...SO HAVE BACKED OFF A BIT ON THE TSRA POTENTIAL IN THE TAFS. STILL FEEL THAT THE BEST TIMING WILL BE AT SOME POINT DURG THE AFTERNOON HOURS...BUT TSRA COULD END UP BEING MORE ISOLD/EMBEDDED THAN ORGANIZED SO HAVE GONE WITH VCTS WORDING. THIS SHOULD STILL COINCIDE WITH THE PASSAGE OF THE SHORTWAVE ALOFT AND THE WEAK COLD FRONT AT THE SURFACE. THE REMAINDER OF THE PERIOD SHOULD THEN BE DRY WITH NWLY WINDS LESS THAN 10KT AND VFR CIGS/VIS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM CONFIDENCE OF INCREASING SHRA COVERAGE AND ONLY ISOLATED TSRA. * MEDIUM CONFIDENCE ON WIND DIRECTION TRENDS...HIGHER CONFIDENCE ON SPEED TRENDS. * HIGH TO MEDIUM CONFIDENCE OF PREVAILING VFR WITH BRIEF MVFR. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. THURSDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE TSRA. OTHERWISE VFR. SUNDAY...SLIGHT CHANCE TSRA. OTHERWISE VFR. KREIN && .MARINE... 315 AM CDT BROAD HIGH PRESSURE EXTENDS FROM THE GREAT LAKES REGION ACROSS MUCH OF THE EAST COAST. THE RESULTANT LIGHT AND VARIABLE WINDS COMBINED WITH RESIDUAL HIGH DEWPOINT AIR OVER THE STILL VERY COLD LAKE WATERS HAS KEPT DENSE FOG IN PLACE. THE DENSE FOG WILL CONTINUE WHILE THE HIGH PRESSURE IS SLOWLY ERODED BY A TROUGH OF WEAK LOW PRESSURE AS IT MOVES ACROSS THE MISSISSIPPI VALLEY MONDAY MORNING. THE TROUGH AND AN ASSOCIATED WEAK COLD FRONT WILL MOVE ACROSS THE LAKE LATE MONDAY NIGHT TURNING WINDS FROM LIGHT AND VARIABLE TO WESTERLY AND NORTHWESTERLY...WHICH WILL BEGIN TO SCOUR OUT THE FOG FROM THE LAKE. A SECONDARY COLD FRONT WILL DROP DOWN THE LAKE TUESDAY TURNING WINDS NORTHERLY BRINGING AN END TO ANY RESIDUAL FOG AS DRIER AIR FILTERS OVER THE LAKE. HIGH PRESSURE WILL BUILD ACROSS THE UPPER LAKES WEDNESDAY AND THURSDAY KEEPING CONDITIONS OVER THE LAKE RELATIVELY QUIET...BUT BY THE END OF THE WEEK...STRENGTHENING SOUTHERLY WINDS OF 15 TO 25 KT WILL DEVELOP OVER THE LAKE AS THE HIGH MOVES OFF TO THE EAST AND ANOTHER TROUGH APPROACHES FROM THE WEST. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1109 AM CDT MON JUN 23 2014 .DISCUSSION... 305 AM CDT A HANDFUL OF FORECAST CHALLENGES THIS FINAL FULL WEEK OF JUNE...ALTHOUGH IT DOES APPEAR TO BE A MORE QUIET WEEK THAN LAST...WITH LESS WIDESPREAD STORM/HEAVY RAINFALL CHANCES. ITEMS OF CONCERN THIS MORNING INCLUDE RAIN AND THUNDER COVERAGE TODAY AS WELL AS FOG POSSIBILITIES NEAR THE LAKE SHORE. TODAY AND TONIGHT... ONCE AGAIN THIS MORNING IT IS A MESSY MID-LEVEL PATTERN WITH MULTIPLE SMALL SCALE IMPULSES FROM KS TO WI SEEN ON A LONG LOOP OF SATELLITE WATER VAPOR CHANNEL. OVERALL THOUGH THESE FEATURES COMPOSE AN UPPER SHORT WAVE TROUGH THAT WILL INCH EASTWARD LIKELY CLEARING THE AREA BY OR DURING OVERNIGHT. QG FORCING FOR ASCENT IN ADVANCE OF THIS TROUGH...WITHIN A MOIST AIR MASS OF PRECIPITABLE WATER OBSERVED OF 1.50-1.75 INCHES...SHOULD SUPPORT MODEST COVERAGE OF SHOWERS ESPECIALLY THROUGH EARLY AFTERNOON. SCATTERED/EMBEDDED THUNDER WILL BE MOST PRONOUNCED AHEAD OF ANY OF THE AFOREMENTIONED IMPULSES...WITH 500-1200 J/KG OF MUCAPE TO WORK WITH THROUGH THE MORNING PER CURRENT AMDAR DATA AND RAP FORECASTS THROUGH MIDDAY. DID OUR BEST TO ADD TEMPORAL RESOLUTION IN THE FORECAST OF HIGHER POPS TODAY...WITH THE GREATER LIKELIHOOD SHIFTING SLOWLY EAST DURING THE DAY. CONVECTIVE ALLOWING GUIDANCE INDICATES SOME POSSIBLY DEEPER CONVECTION NEAR MIDDAY/EARLY AFTERNOON ACROSS THE EASTERN FORECAST AREA...ASSOCIATED WITH INSTABILITY BECOMING MORE ROOTED IN THE MIXED LAYER GIVEN SURFACE HEATING. WITH WEAK DEEP LAYER SHEAR /AOB 25 KT/ AND ANY MODEST DCAPE BEING CONDITIONAL ON SOME SUNSHINE WHICH THERE MAY NOT BE TOO MUCH OF...THINK SEVERE STORM POTENTIAL IS SMALL AND THAT CHANCE CONFINED TO THE EASTERN FORECAST AREA. OBSERVATIONS AND WEBCAMS EARLY THIS MORNING ARE INDICATING THE LEAST DENSE THE FOG HAS BEEN NEAR THE LAKE SHORE IN SEVERAL MORNINGS. THUS ITS POSSIBLE THE ADVISORY MAY BE CANCELLED NEAR SUNRISE DEPENDING ON HOW THINGS LOOK. A LIGHT FLOW PATTERN TODAY MAY FAVOR A LAKE BREEZE...THOUGH SHOWERS AND POSSIBLE STORMS COULD DISRUPT THE WIND FIELD AND LAKE FOG. IN ADDITION...LATE DAY VISIBLE SATELLITE IMAGERY FROM SUNDAY INDICATED THE FOG OVER SOUTHERN LAKE MI HAD BECOME MORE THIN...SO NOT EXPECTING FOG TO BE A BIG DEAL MUCH OF TODAY ALONG THE LAKE SHORE. DEPENDING ON EXACT FRONTAL TIMING...SOME PATCHY FOG MAY SPREAD BRIEFLY INLAND AGAIN THIS EVENING...AND POSSIBLY INTO NORTHWEST INDIANA OVERNIGHT BEHIND FROPA WITH THE SYNOPTIC FLOW SHIFTING NORTH-NORTHWEST. TUESDAY THROUGH THURSDAY... A LITTLE MORE OF A NORTHWEST PUSH ARRIVES ON TUESDAY AFTERNOON OR EVENING BEHIND A SECONDARY COOL FRONT. ALONG THIS FEATURE ON TUESDAY AFTERNOON THERE COULD BE ISOLATED SHOWERS/STORMS AS A JET STREAK AND ASSOCIATED RIGHT ENTRANCE REGION MOVE OVER THE BOUNDARY DURING PEAK HEATING. HAVE MAINTAINED THE CHANCES FOR PRECIP ONLY IN THE NORTHERN FORECAST AREA ON TUESDAY AS THIS FEATURE APPROACHES. SEMI-ZONAL FLOW IS FORECAST TO PERSIST THROUGH MIDWEEK WITH LITTLE TO KEY IN ON FOR SHOWER OR STORM CHANCES. WARM AIR ADVECTION AND POSSIBLY A SHORT WAVE DEPENDING ON WHICH LONG RANGE MODEL ONE LOOKS AT INDICATE SOME STORM POTENTIAL LATER THURSDAY...BUT OVERALL NOT TOO EXCITED ABOUT THIS AT THIS POINT. TEMPERATURES LOOK TO COOL SLIGHTLY WEDNESDAY AND THURSDAY...ALTHOUGH MORE SO NEAR THE LAKE SHORE. THIS IS ESPECIALLY TRUE ON WEDNESDAY WHICH LOOKS TO HAVE SHORELINE HIGHS STRUGGLE TO REACH 70. FRIDAY INTO NEXT WEEKEND... ENERGY FROM A PERSIST GULF OF ALASKA TROUGH IS EXPECTED TO EVOLVE INTO THE NORTHWEST U.S. AND WESTERN CANADA DURING THIS PERIOD AND IN RESPONSE HEIGHTS WILL BUILD ACROSS THE MISSISSIPPI AND OHIO RIVER VALLEY REGIONS. THE EC HAS TRENDED DOWN FROM THE HEIGHTS AND 850MB TEMPS IT HAD 24 HOURS AGO...BUT STILL SUPPORTIVE OF AROUND 90 DEGREES FOR WEEKEND HIGHS IF NOT IMPACTED BY ANY CONVECTION...WHICH THERE LOOKS TO BE AT LEAST SMALL CHANCES FOR AT THIS POINT. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * INCREASING SHRA COVERAGE EXPECTED THROUGH MID AFTERNOON...WITH ISOLATED TSRA. * POSSIBLE MVFR CIGS/VSBYS IN HEAVIER SHOWERS BUT GENERALLY VFR. * VARIABLE WINDS...SOUTHERLY TO SOUTHWESTERLY...VEERING WEST LATE. LENNING //DISCUSSION...UPDATED 12Z... THE PCPN FORECAST REMAINS THE MAIN CONCERN WITH SOME UNCERTAINTY CONTINUING WITH THE TSRA POTENTIAL. THE ENVIRONMENT OVER THE AREA REMAINS VERY MOIST AND SHOULD BECOME AT LEAST WEAKLY UNSTABLE THROUGH THE DAY. A MODERATE SHORTWAVE ALOFT HAS BEEN CONSISTENTLY FORECAST BY THE MODELS TO CROSS THE REGION THIS AFTERNOON...AND WILL BE ACCOMPANIED BY A WEAK COLD FRONT. FRONTAL FORCING WILL BE LOW AS THERE WILL BE ONLY A MINOR AIRMASS CHANGE WITH THE FRONTAL PASSAGE AND A WINDSHIFT FROM LIGHT SOUTHERLY WINDS TO LIGHT NWLY WINDS. THERE MAY BE A FEW GUSTS TO ARND 15KT IN THE WEAK WARM ADVECTION AHEAD OF THE FRONT...BUT WINDS SHOULD BE LESS THAN 10KT BEHIND THE FRONT. THE LATEST GUIDANCE AND SATELLITE TRENDS INDICATE A WEAKER SHORTWAVE ALOFT THAN PREVIOUSLY NOTED...SO HAVE BACKED OFF A BIT ON THE TSRA POTENTIAL IN THE TAFS. STILL FEEL THAT THE BEST TIMING WILL BE AT SOME POINT DURG THE AFTERNOON HOURS...BUT TSRA COULD END UP BEING MORE ISOLD/EMBEDDED THAN ORGANIZED SO HAVE GONE WITH VCTS WORDING. THIS SHOULD STILL COINCIDE WITH THE PASSAGE OF THE SHORTWAVE ALOFT AND THE WEAK COLD FRONT AT THE SURFACE. THE REMAINDER OF THE PERIOD SHOULD THEN BE DRY WITH NWLY WINDS LESS THAN 10KT AND VFR CIGS/VIS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM CONFIDENCE OF INCREASING SHRA COVERAGE AND ONLY ISOLATED TSRA. * MEDIUM CONFIDENCE ON WIND DIRECTION TRENDS...HIGHER CONFIDENCE ON SPEED TRENDS. * HIGH TO MEDIUM CONFIDENCE OF PREVAILING VFR WITH BRIEF MVFR. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. THURSDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE TSRA. OTHERWISE VFR. SUNDAY...SLIGHT CHANCE TSRA. OTHERWISE VFR. KREIN && .MARINE... 315 AM CDT BROAD HIGH PRESSURE EXTENDS FROM THE GREAT LAKES REGION ACROSS MUCH OF THE EAST COAST. THE RESULTANT LIGHT AND VARIABLE WINDS COMBINED WITH RESIDUAL HIGH DEWPOINT AIR OVER THE STILL VERY COLD LAKE WATERS HAS KEPT DENSE FOG IN PLACE. THE DENSE FOG WILL CONTINUE WHILE THE HIGH PRESSURE IS SLOWLY ERODED BY A TROUGH OF WEAK LOW PRESSURE AS IT MOVES ACROSS THE MISSISSIPPI VALLEY MONDAY MORNING. THE TROUGH AND AN ASSOCIATED WEAK COLD FRONT WILL MOVE ACROSS THE LAKE LATE MONDAY NIGHT TURNING WINDS FROM LIGHT AND VARIABLE TO WESTERLY AND NORTHWESTERLY...WHICH WILL BEGIN TO SCOUR OUT THE FOG FROM THE LAKE. A SECONDARY COLD FRONT WILL DROP DOWN THE LAKE TUESDAY TURNING WINDS NORTHERLY BRINGING AN END TO ANY RESIDUAL FOG AS DRIER AIR FILTERS OVER THE LAKE. HIGH PRESSURE WILL BUILD ACROSS THE UPPER LAKES WEDNESDAY AND THURSDAY KEEPING CONDITIONS OVER THE LAKE RELATIVELY QUIET...BUT BY THE END OF THE WEEK...STRENGTHENING SOUTHERLY WINDS OF 15 TO 25 KT WILL DEVELOP OVER THE LAKE AS THE HIGH MOVES OFF TO THE EAST AND ANOTHER TROUGH APPROACHES FROM THE WEST. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM MONDAY. && $$ 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...UPDATED
NWS DODGE CITY KS
346 PM CDT Mon Jun 23 2014 ...Updated for Long Term... .SHORT TERM...(This evening through Tuesday) ISSUED AT 300 PM CDT MON JUN 23 2014 Another MCS night likely across far western Kansas. There is isolated weak thunderstorms developing across south central Kansas this afternoon as well. Have the highest pops along and west of Garden City to Liberal, although the most recent HRRR propagates the MCS farther east. Something to watch and update ESTF grids based on reality rather than model output solutions. There could be some severe weather across far western Kansas as meso analyzed SBCAPES are near 2000 J/kg and 30 kt effective bulk shear. Most probable threat is hail and winds along with heavy rainfall as pwats remain just below the 75th percentile for a normal distribution. Overnight minimums will be in the 60sF. Another MCS likely tomorrow. Attempted to add some diurnal pop variability with a minimum towards 18Z and maximum at the end of my period. Some uncertainty in storm placement as convective allowing models are different than the global models. Broad bushed pops at this point as pwats remain high and the overall synoptic pattern is that which is conducive for MCS`s. There could be some marginal severe weather again as instability is moderate and bulk shear is more marginal. Highs in the 80sF. .LONG TERM...(Tuesday night through Monday) ISSUED AT 344 PM CDT MON JUN 23 2014 For Tuesday night, a weak upper level shortwave trough will be moving across western Kansas with numerous showers and thunderstorms expected as an MCS. At this time with weak wind shear and instability the chances for severe do not look that promising. Have upped precip chances. Overnight lows will be in the mid 60s. On Wednesday, more widely scattered thunderstorms are possible with moderate instability mainly by late afternoon. The upper level winds again look weak with severe thunderstorms not a good bet. Highs will be in the mid to upper 80s. For the period Thursday into next Monday, the best chance for more scattered thunderstorms looks to be on Thursday with another weak upper level wave. A stronger wave moves from the Pacific Northwest and into the Northern Plains by the Weekend with the best chance for thunderstorms mainly far north across I-70. Lows will be mild in the upper 60s to lower 70s, with highs warming slowly from the upper 80s into the low to mid 90s by the Weekend. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 1200 PM CDT MON JUN 23 2014 VFR mainly expected. Some local MVFR here in KDDC, but this won`t last long. CB`s likely to impact KGCK this evening with fairly strong outflow winds as main aviation impact. && .PRELIMINARY POINT TEMPS/POPS... DDC 63 85 65 87 / 20 40 50 30 GCK 62 85 64 87 / 50 40 50 20 EHA 62 84 64 89 / 50 40 50 30 LBL 63 87 64 88 / 50 40 50 30 HYS 63 82 64 85 / 20 20 40 30 P28 65 86 68 86 / 10 30 40 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Sugden LONG TERM...Kruse AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
300 PM CDT Mon Jun 23 2014 ...Update to short term... .SHORT TERM...(This evening through Tuesday) ISSUED AT 300 PM CDT MON JUN 23 2014 Another MCS night likely across far western Kansas. There is isolated weak thunderstorms developing across south central Kansas this afternoon as well. Have the highest pops along and west of Garden City to Liberal, although the most recent HRRR propagates the MCS farther east. Something to watch and update ESTF grids based on reality rather than model output solutions. There could be some severe weather across far western Kansas as meso analyzed SBCAPES are near 2000 J/kg and 30 kt effective bulk shear. Most probable threat is hail and winds along with heavy rainfall as pwats remain just below the 75th percentile for a normal distribution. Overnight minimums will be in the 60sF. Another MCS likely tomorrow. Attempted to add some diurnal pop variability with a minimum towards 18Z and maximum at the end of my period. Some uncertainty in storm placement as convective allowing models are different than the global models. Broad bushed pops at this point as pwats remain high and the overall synoptic pattern is that which is conducive for MCS`s. There could be some marginal severe weather again as instability is moderate and bulk shear is more marginal. Highs in the 80sF. .LONG TERM...(Tuesday through Sunday) ISSUED AT 323 AM CDT MON JUN 23 2014 The overall wet pattern, with nightly mesoscale convective systems (MCS), will continue through Wednesday Night. This pattern will not break until we see more pronounced ridging develop over the Rockies...which is expected by Thursday with height rises ahead of a West Coast trough/Pacific jet. Lower-mid tropospheric temperatures will warm substantially as a result. This will force the overall convective activity into the Northern High Plains as a general rule Thursday and Friday...and probably into Saturday as well. There is still quite a bit of difference between the ECMWF and the GFS regarding the strength and evolution of the polar jet as it penetrates the central CONUS. The ECMWF is a bit further south with the jet core, which would keep western Kansas in play for severe thunderstorm risk, whereas the GFS would keep western Kansas dry amidst warm mid level temperatures with the jet core centered across the Dakotas. Surface temperatures will slowly increase through the period, too, with lower 90s back in the forecast by late week and next weekend. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 1200 PM CDT MON JUN 23 2014 VFR mainly expected. Some local MVFR here in KDDC, but this won`t last long. CB`s likely to impact KGCK this evening with fairly strong outflow winds as main aviation impact. && .PRELIMINARY POINT TEMPS/POPS... DDC 63 85 65 87 / 20 40 40 30 GCK 62 85 65 87 / 50 40 50 20 EHA 62 84 64 90 / 50 40 50 20 LBL 63 87 65 89 / 50 40 50 20 HYS 63 82 66 87 / 20 20 30 30 P28 65 86 68 88 / 10 30 30 30 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Sugden LONG TERM...Umscheid AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
349 PM EDT MON JUN 23 2014 .SHORT TERM...THIS AFTERNOON AND TONIGHT AT 19Z THE SURFACE WARM FRONT WAS DRAPED ROUGHLY ALONG THE MICHIGAN STATE BORDER PER REGIONAL OBSERVATIONS. NORTH OF THE FRONT, SHOWERS ASSOCIATED WITH THIS MORNING`S MCV CONTINUE EXITING EAST. THIS LIGHT PRECIP AND ASSOCIATED CLOUD COVER HAS KEPT TEMPERATURES CONFINED TO THE LOW/MID 70S THROUGH MID-AFTERNOON. SOUTH OF THE WARM FRONT, TEMPERATURES IN THE MID 80S AND DEWPOINTS NEAR 70 ARE CONTRIBUTING TO A MODERATE TO STRONGLY UNSTABLE ENVIRONMENT CHARACTERIZED BY A WEAK/UNIDIRECTIONAL AMBIENT WIND FIELD. WITHIN SAID WARM SECTOR, WIDESPREAD MULTICELL CONVECTION IS ONGOING WITH ONLY ISOLATED SEVERE REPORTS THUS FAR. HOWEVER, SUFFICIENT BOUNDARY LAYER RECOVERY SOUTH OF THE WARM FRONT, MOST LIKELY SOUTH OF I-94, WILL HAVE THE POTENTIAL TO CONTRIBUTE TO A WELL-MIXED ENVIRONMENT THROUGH THE LOWEST 5KFT PER THE LATEST RAP FORECAST SOUNDINGS. THIS, IN THE PRESENCE OF LOCALLY ENHANCED SHEAR INVOF THE WARM FRONT, WILL PRESENT A LOW-END CHANCE FOR BRIEF ORGANIZED UPDRAFTS CAPABLE OF PRODUCING A MARGINAL DIABATICALLY-INDUCED SEVERE WIND THREAT UNTIL DIURNAL HEATING IS LOST LATER THIS EVENING. THUNDERSTORM POTENTIAL WILL PERSIST THROUGH THE NIGHT AS THE AREA BECOMES INCREASINGLY ENTRENCHED IN THE WARM SECTOR. ONE LINE OF THUNDERSTORMS HAS DEVELOPED ALONG A LINE FROM SOUTH BEND TO TERRE HAUTE ALONG THE LEAD EDGE OF THE MID-LEVEL MOISTURE TRANSPORT AXIS. IN ADDITION, MORE UPSTREAM DEVELOPMENT HAS BEGUN JUST SOUTH OF CHICAGO IN ASSOCIATION WITH AN MCV EVIDENT IN AFTERNOON VISIBLE IMAGERY. THIS ACTIVITY WILL SPREAD EAST THROUGH MIDNIGHT, WITH THE LAST ROUND LIKELY AFFECTING THE METRO AREA SOMETIME AROUND 02-03Z. THE PRIMARY THREATS WITH LATE EVENING/EARLY NIGHT ACTIVITY WILL BE HEAVY RAIN DUE TO POTENTIAL TRAINING AND PWATS OF 1.6" TO 1.8" ALONG WITH LIGHTNING. SEVERE WIND POTENTIAL WILL DIMINISH WITH TIME AS THE SUN ANGLE DECREASES. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH TONIGHT AS THE MID-LEVEL THERMAL GRADIENT RESPONDS TO AN ENCROACHING NORTHERN STREAM WAVE. THE AGEOSTROPHIC RESPONSE SHOULD BE JUST ENOUGH TO KEEP ACTIVITY BUBBLING WITHIN THE MOISTURE AXIS THROUGH THE NOCTURNAL PERIOD. LOWS IN THE WARM SECTOR WILL STRUGGLE TO FALL BELOW 70 DEGREES. && .LONG TERM...TUESDAY THROUGH SUNDAY GENERALLY ILL-DEFINED FORCING IN A MOIST ENVIRONMENT /PW 1.5-2 INCHES/ POSES CHALLENGES FOR DETERMINING POPS TUESDAY...BUT TRIED TO KEY IN ON SOME FEATURES WITH THIS PACKAGE. WEAK SURFACE CIRCULATION WILL BE LOCATED NEAR CENTRAL LAKE HURON AT 12Z TUESDAY AND MOVING NORTHEAST...LIKELY ACCOMPANIED BY AN AREA OF SHOWERS/T-STORMS. A WEAK SURFACE TROUGH WILL EXTEND SOUTHWARD FROM THIS LOW...BISECTING LOWER MICHIGAN. MEANWHILE...A SHORTWAVE CURRENTLY NOTED ON WATER VAPOR OVER OKLAHOMA WILL PROGRESS NORTHEASTWARD...REACHING IN/OH BY 00Z WEDNESDAY. WEAK AREA OF MIDLEVEL DEFORMATION NORTH OF THIS WAVE MAY PROVIDE SOME LIFT OVER SE MI...ALONG WITH RIGHT ENTRANCE REGION FORCING FROM 70KT JET OVER NORTHERN LOWER. HAVE HIGHLIGHTED THIS FORCING BY UPGRADING THE SOUTHEAST THIRD OF THE CWA TO ENTRY-LEVEL LIKELY POPS FROM 15-21Z. ALSO LOWERED HIGHS A COUPLE DEGREES OVER THE SOUTH TO ACCOUNT FOR EXPECTED ACTIVITY. OTHERWISE...SHOWER/STORM ACTIVITY IS POSSIBLE IN THE MORNING ALONG THE SURFACE TROUGH. SEVERE POTENTIAL DOES NOT LOOK TOO OVERWHELMING...ESPECIALLY IF MORNING ACTIVITY HAMPERS DESTABILIZATION. MIDLEVEL LAPSE RATES ARE NOT TOTALLY IMPRESSIVE AT 6-6.5 K/KM. IF PRECIP HOLDS OFF UNTIL LATER AND SOME MORE RESPECTABLE INSTABILITY DEVELOPS...BULK SHEAR INCREASING TO AROUND 30 KT COULD RESULT IN SOME BETTER ORGANIZED ACTIVITY...BUT CONFIDENCE IS LOW IN THAT SCENARIO. LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN THE MOIST ENVIRONMENT...ESPECIALLY IN ANY MORE ORGANIZED ACTIVITY. THE SOUTHWARD PUSH OF THE EAST/WEST ORIENTED COLD FRONT SHOULD SPELL AN END TO MOST POPS AFTER 00Z...THOUGH IT IS NOT A VERY AGRESSIVE FRONTAL PUSH...SO LOW TEMPS TUESDAY NIGHT SHOULD REMAIN IN THE 60S. LOWER THETA-E AIR WILL CONTINUE TO FILTER IN ON WEDNESDAY AS SURFACE ANTICYCLONE OVER ONTARIO ATTEMPTS TO EXPAND SOUTHWARD INTO LOWER MI. THIS WILL BE COMPLICATED BY THE PASSAGE OF A MIDLEVEL SHORTWAVE DURING THE DAY. MODEL SOUNDINGS SHOW A DECIDED LACK OF MIDLEVEL MOISTURE HOWEVER...SO KEPT THE FORECAST DRY. GFS IS SHOWING MOISTURE TRAPPED UNDER AN INVERSION AROUND 900MB FOR MOST OF THE DAY...SO HAVE KEPT A DECENT AMOUNT OF CLOUD COVER AROUND UNTIL THE AFTERNOON. HIGHS WILL BE A BIT COOLER THAN TUESDAY IN THE MID-70S TO NEAR 80. THE HIGH WILL HAVE MORE SUCCESS BUILDING IN WEDNESDAY NIGHT AS DRIER AIR CONTINUES TO FILTER IN...SO EXPECTING CLEARING SKIES AND LOWS MAINLY IN THE 50S. HIGH PRESSURE BUILDS SOUTHWARD INTO THE GREAT LAKES ON THURSDAY AND WILL SLOWLY DRIFT EASTWARD THROUGH FRIDAY. THIS HIGH WILL ALLOW DRY CONDITIONS TO STICK AROUND FOR THE END OF THE WEEK BEFORE A LOW PRESSURE SYSTEM MOVES NORTHWARD TOWARDS SOUTHEAST MICHIGAN LATE SATURDAY AND INTO SUNDAY. THE LOW WILL BRING RAIN SHOWERS AND POSSIBLY THUNDERSTORMS TO THE AREA THROUGH THE FIRST PART OF NEXT WEEK. HIGH TEMPERATURES ARE EXPECTED TO REMAIN STEADY THROUGH THE END OF THE WEEK IN THE MID TO UPPER 70S BEFORE RISING INTO THE LOW TO MID 80S FOR THE WEEKEND. LOW TEMPERATURES WILL REMAIN STEADY IN THE LOW TO MID 60S THROUGH THE EXTENDED PERIOD. && .MARINE... ACTIVE STRETCH OF WEATHER WILL PERSIST INTO MID WEEK FOR THE EASTERN GREAT LAKES AS A PAIR OF FRONTS WORK THROUGH THE AREA. THE FIRST FRONT IS DRAPED ALONG A LINE FROM LAKE ONTARIO AND LAKE ERIE...SOUTHWEST INTO THE OHIO VALLEY AND WILL PRODUCE SHOWERS AND THUNDERSTORMS THROUGH TUESDAY. THIS WILL VEER WINDS FROM SOUTHERLY TO WESTERLY. A SECOND COLD FRONT WILL DROP SOUTHWARD OUT OF CANADA THROUGH THE EASTERN LAKES TUESDAY AND WEDNESDAY AND WILL USHER NORTHERLY WINDS DOWN THROUGH LAKE HURON. A WEAK PRESSURE GRADIENT WILL KEEP WINDS LIGHT THROUGH THE PERIOD...GENERALLY LESS THAN 15 KNOTS...WHICH IN TURN WILL KEEP THE WAVES IN CHECK. && .AVIATION...ISSUED 1253 PM EDT MON JUN 23 2014 //DISCUSSION... LOW VFR CONDITIONS AND LIGHT SHOWERS HAVE OVERSPREAD THE AREA EARLY THIS AFTERNOON. SHOWERS AND A FEW EMBEDDED TSTORMS WILL PERSIST FOR THE NEXT FEW HOURS BEFORE TAPERING EXITING TO THE EAST. AN ISOLATED SHOWER OR THUNDERSTORM WILL THEN BE POSSIBLE INTO THE EVENING, WITH THE NEXT ORGANIZED BATCH OF ACTIVITY EXPECTED TO MOVE THROUGH BETWEEN 01Z-05Z. LOW CONFIDENCE IN COVERAGE FOR TONIGHT SO ELECTED TO REDUCE PREVAILING -SHRA TO A PROB30 GROUP. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILINGS BELOW 5KFT * LOW CONFIDENCE IN TSTORMS AFFECTING KDTW && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...JVC LONG TERM....DRK/RK MARINE.......DRK AVIATION.....JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
112 PM EDT MON JUN 23 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 522 AM EDT MON JUN 23 2014 WV IMAGERY AND RUC ANALYSIS INDICATED WSW FLOW INTO THE NRN LAKES BETWEEN A MID/UPPER LEVEL TROUGH FROM MANITOBA INTO THE NRN PLAINS AND A RIDGE FROM THE OHIO VALLEY INTO QUEBEC. AT THE SFC...A WEAK TROUGH EXTENDED FROM NE MN INTO WRN WI. A MORE PROMINENT COLD FRONT STRETCHED FROM JAMES BAY TO NEAR WINNIPEG AHEAD OF HIGH PRESSURE OVER N CNTRL CANADA. FORCING FROM A WEAK SHRTWV IN NRN WI ALONG WITH AN AXIS OF HIGHER MOISTURE WITH PWAT VALUES TO 1.4 INCHES...WAS ENOUGH TO SUPPORT AN AREA OF SHOWERS OVER FROM SW UPPER MI INTO E CNTRL WI. TODAY...EXPECT THE SHRTWV AND AREA OF PCPN ONLY SLOWLY MOVE TO THE EAST THIS MORNING. WITH ONLY WEAK LARGE SCALE FORCING EXPECTED INTO THE AFTERNOON AND THE POTENTIAL FOR ANOTHER WEAK SHRTWV TO MOVE INTO THE AREA DURING INCREASED DAYTIME HEATING...THE FCST KEEPS MENTION OF JUST SCT SHRA WITH THE GREATEST COVERAGE EXPECTED OVER CNTRL UPPER MI. WITH TEMPS CLIMBING INTO THE MID 70S...THERE MAY BE ENOUGH INSTABILITY FOR SOME ISOLD/SCT TSRA AS MLCAPE VALUES CLIMB INTO THE 400-800 J/KG RANGE. TONIGHT...WITH THE LOSS OF DAYTIME HEATING...THE PCPN COVERAGE SHOULD DIMINISH. HOWEVER...INCREASED QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH MOVING INTO THE UPPER MS VALLEY WILL SUPPORT CONTINUED CHANCES FOR SCT SHOWERS AND A FEW TSRA. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 421 AM EDT MON JUN 23 2014 ON TUESDAY MORNING...THE MODELS ARE IN GOOD AGREEMENT IN SHOWING THE COLD FRONT MOVING OVER OR JUST SOUTH OF THE AREA. HOWEVER...THE 850MB TROUGH AXIS HANGS UP OVER LAKE SUPERIOR AS THERE IS LACK OF A SOUTHWARD PUSH DUE TO THE GENERAL ZONAL FLOW ALOFT. THIS WILL PROVIDE THE FOCUS FOR PRECIPITATION ON TUESDAY ESPECIALLY SINCE THE MODELS ARE IN EXCELLENT AGREEMENT IN SHOWING BROAD SYNOPTIC SUPPORT MOVING THRU AS THE 500MB TROUGH AXIS MOVES THROUGH. AS SUCH...THERE WILL LIKELY BE SCATTERED SHOWERS ACROSS THE ENTIRE FORECAST AREA THROUGH THE DAY DESPITE THE SURFACE FRONT BEING SOUTH OF THE REGION. THE NUMERICAL GUIDANCE ALSO SHOWS MUCAPE VALUES OF 500-1500 J/KG ACROSS THE REGION DURING THE DAY WITH MID LEVEL LAPSE RATES OF 6+ C/KM...ALLOWING FOR POSSIBLE THUNDERSTORM DEVELOPMENT. BEST CHANCES FOR THUNDER WOULD BE ACROSS THE SOUTHERN TIER WHERE SFC TEMPS WILL LIKELY BE IN THE LOWER-MID 70S AND IS WHERE THE BEST INSTABILITY WILL BE LOCATED. WILL NEED TO KEEP CHANCE POPS ACROSS THE EASTERN HALF OF THE FORECAST AREA DURING THE TUE EVENING HOURS AS WELL GIVEN REMAINING MID LEVEL FORCING AND REMAINING DAYTIME INSTABILITY. AT THIS TIME...WEDNESDAY IS EXPECTED TO REMAIN DRY AND COOL WITH THE 850MB TROUGH AND SFC FRONT REMAINING SOUTH OF THE AREA. STILL SOME WEAK TROUGHINESS AT 500MB AND AS SUCH WEAK MID LEVEL Q-VECTOR CONVERGENCE AND MOISTURE PERSISTS ACROSS THE AREA ALL DAY. HOWEVER...GIVEN LACK OF INSTABILITY AND VERY WEAK MID LEVEL LAPSE RATES COMBINED WITH ANTICYCLONIC LOW LEVELS WILL KEEP IT DRY FOR NOW. WOULD NOT BE SHOCKED TO SEE ISOLATED SHOWERS BUT CHANCES ARE NOT HIGH ENOUGH TO INCLUDE IN THE FORECAST AT TIME TIME. IN THE EXTENDED...ZONAL FLOW THROUGH THE PERIOD WILL MAKE TIMING OF PRECIPITATION SOMEWHAT DIFFICULT ESPECIALLY INTO THE WEEKEND. HOWEVER...THE LONGER RANGE MODELS ARE IN DECENT AGREEMENT ON THE BROAD SCALE FEATURES WHICH AT LEAST GIVES SOME BASIC CONFIDENCE ON WHEN THE BETTER CHANCES FOR RAIN WILL BE. ON THURSDAY...THE ECMWF AND GFS BOTH SHOW A COMPACT VORT MAX MOVING ACROSS THE AREA DURING THE DAY AS THE 850MB FRONT MOVES BACK NORTH. ALTHOUGH MOISTURE WILL BE VERY LIMITED...WILL INCLUDE CHANCE POPS FOR THE WESTERN HALF OF THE FORECAST AREA. BEHIND THIS VORT MAX...UPPER RIDGING BUILDS ACROSS THE AREA FOR FRIDAY WHICH SHOULD ALLOW FOR TEMPS TO RETURN TO NORMAL AS WELL AS DRY WEATHER. RETURN FLOW BEGINS IN EARNEST FOR THE WEEKEND WITH TEMPERATURES LIKELY TO RISE ABOVE NORMAL...AND PERHAPS A LITTLE MORE HUMIDITY AND SUMMER LIKE WEATHER. THIS WILL ALLOW FOR CHANCES OF SHOWERS AND STORMS EACH DAY...ALTHOUGH SUNDAY LOOKS LIKE THE BETTER CHANCE FOR SHOWERS AND STORMS GIVEN LOWERING HEIGHTS ACROSS THE AREA IN RESPONSE TO THE APPROACHING TROUGH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 111 PM EDT MON JUN 23 2014 VFR CONDITIONS ARE EXPECTED INTO THIS EVENING. WITH LIGHT WINDS AND ABUNDANT LOW LEVEL MOISTURE REMAINING...FOG IS EXPECTED TO DEVELOP TONIGHT WITH VLIFR CONDITIONS EXPECTED AT ALL SITES. WITH NORTH WINDS TUE MORNING...A SLOW IMRPOVEMENT TO LIFR CONDITIONS ARE EXPECTED WITH MOIST UPSLOPE FLOW CONTINUING TUE MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 522 AM EDT MON JUN 23 2014 DENSE FOG WILL PERSIST OVER WESTERN LAKE SUPERIOR INTO THIS AFTERNOON. OTHERWISE...MAINLY LIGHT WINDS WILL PREVAIL INTO TONIGHT. AS A COLD FRONT MOVES THROUGH THE AREA ON TUESDAY...NORTHEAST WINDS WILL INCREASE TO 20 KNOTS WITH WAVES BUILDING TO AROUND 4 FEET. WINDS WILL DIMINISH TUE NIGHT INTO WED AS HIGH PRES BUILDS INTO THE REGION. MAINLY LIGHT WINDS AT OR BELOW 15 KNOTS ARE THEN EXPECTED THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 8 PM EDT /7 PM CDT/ TUESDAY FOR LSZ162- 240>248-263>265. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MRD AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1247 PM CDT MON JUN 23 2014 .UPDATE... ISSUED AT 1148 AM CDT MON JUN 23 2014 UPDATE TO FURTHER REFINE PRECIP CHANCES THROUGH THE AFTERNOON. WITH VERY SUBTLE FORCING AND LOW LEVEL MOISTURE LIMITED...COVERAGE SHOULD ALSO BE LIMITED. BROAD AREA OF SC HAS DEVELOPED ACROSS THE PORTIONS OF THE SANDHILLS WHICH MAY HAVE A LIMITING FACTOR ON HOW FAST TEMPS RISE THIS AFTERNOON. BELIEVE MODELS PICKING UP ON THIS AREA AS LOCATION OF SHRA/TSRA BUT LITTLE VERTICAL DEVELOPMENT NOTED ON VISIBLE SAT PICS AT THIS TIME...AND MID LEVEL LAPSE RATES ARE NOT CONDUCIVE YET FOR THAT. HIGHER TERRAIN FURTHER WEST SHOULD BE THE INITIATION FOR TSRA DEVELOPMENT LATER THIS AFTERNOON AND CONFIDENCE IS LOW THAT MUCH WILL ENTER THE FORECAST AREA UNTIL LATER THIS EVENING...AFTER A MORE ORGANIZED CONVECTIVE SYSTEM EMERGES FROM NERN CO AND MOVES EWD. UPDATE ISSUED AT 929 AM CDT MON JUN 23 2014 AS MCS CONTINUES TO WEAKEN AND MOVE OUT CI SHIELD ALSO PROGRESSING EWD. VISIBLE SAT PICS INDICATING POCKETS OF ELEVATED INSTABILITY IN THE FORM OF ENHANCEMENT OF AC LIKELY ON LEFTOVER BOUNDARIES. SHORT TERM MODELS CONTINUE TO SHOW SOME THREAT OF ISOLD SHOWERS AND MAYBE A COUPLE TSRA THROUGH THE MORNING INTO EARLY AFTERNOON LIKELY AS RESULT OF LOCAL CONVERGENCE ENHANCEMENT AS SUBTLE UPPER PV ANOMALY MOVES OUT OF SRN WY. WILL HAVE TO INVESTIGATE THIS A BIT MORE FOR THE AFTERNOON IN ORDER TO FURTHER REFINE BEST PRECIP CHANCES. OTHERWISE TEMPS AND DEW POINTS LOOK ON TRACK FOR NOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 319 AM CDT MON JUN 23 2014 ANOTHER MCS SHOULD DROP THROUGH THE CNTL HIGH PLAINS THIS AFTN. THE FORECAST USES 50 PERCENT OF THE RAP MODEL AND 50 PERCENT OF THE OTHER MODELS. THE ONGOING MCS APPEARS TO BE TAKING ON A CYCLONIC ROTATION WITH THE WARM SECTOR ACROSS SCNTL NEB AND THE UPPER LEVEL COLD POOL ACROSS SWRN NEB ATTM. RADAR TRENDS SUGGEST THIS SYSTEM COULD ROTATE THROUGH SCNTL NEB THIS MORNING AND SHOWERS AND TSTMS ARE POPPING LEFT AND RIGHT BETWEEN KLBF AND KLXN. FOR TONIGHT...NEBULOUS POPS ARE IN THE FCST ACROSS THE SANDHILLS AND AREAS SOUTH. GIVEN THE INABILITY OF THE SYNOPTIC SCALE MODELS TO PREDICT NOCTURNAL RAIN EVENTS OF LATE...THE FCST IS FORCED TO MAINTAIN A SCATTERED POP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 319 AM CDT MON JUN 23 2014 12Z TUESDAY AND BEYOND. NEAR DAILY PRECIPITATION CHANCES TO HEADLINE THE EXTENDED DISCUSSION THROUGH AT LEAST SATURDAY AS THE ACTIVE PATTERN CONTINUES. A BRIEF PERIOD OF NORTHWEST FLOW ALOFT WILL DIRECT TWO SUBTLE DISTURBANCES ACROSS THE CENTRAL PLAINS TUESDAY INTO WEDNESDAY. THE FIRST OF WHICH SHOULD BE EAST OF THE CWA BY 12Z TUESDAY. THERE REMAINS GOOD CONSENSUS HOWEVER THAT THUNDER CHANCES REMAIN THROUGH MUCH THE DAY AS THE NEXT DISTURBANCE FOLLOWS. THE ATMOSPHERE WILL CHARACTERIZED AS MODERATELY UNSTABLE...WITH GENERALLY 25-40 KTS OF DEEP LAYER SHEAR. STRONG TO SEVERE STORMS ARE ANTICIPATED...BUT POSSIBLY THE GREATER IMPACT WILL BE HEAVY RAINFALL POTENTIAL AS THERE/S SUPPORT OF ONE OR MORE MCS/S PASSING THROUGH THE SANDHILLS REGION. STORM MOTION WILL BE ON THE SLOW SIDE...GENERALLY LESS THAN 20KTS...AND WITH PWATS INCREASING OVER AN INCH AND A THIRD...RAINFALL RATES OF AN INCH OR TWO AN HOUR WILL BE POSSIBLE. UPPER LOW PRESSURE TO BUILD EAST INTO THE PACIFIC NORTHWEST WEDNESDAY ALLOWING THE EASTWARD DEVELOPMENT OF A LOW AMPLITUDE TRANSITORY RIDGE. PRECIPITATION CHANCES CONTINUE ON WEDNESDAY AS THE NEXT WAVE EMBEDDED IN THE NOW QUASI-ZONAL FLOW IMPACTS THE REGION. TIMING AND PLACEMENT OF THE BETTER PRECIPITATION CHANCES WILL BE GENERALLY TIED TO THE LOCATION OF A LOW LEVEL FRONTAL BOUNDARY AND HOW CONVECTION FROM THE PREVIOUS DAY PLAYS OUT. AT THIS TIME THE MODELS ARE FAVORING NORTHERN NEBRASKA WITH THE HIGHER POP CHANCES /40 PERCENT/ WEDNESDAY AFTERNOON...WILL FOLLOW SUIT WITH THE FORECAST. THE AFOREMENTIONED RIDGE MAY EFFECTIVELY CAP THE REGION ON THURSDAY AS MIDLEVEL TEMPS WARM AOA 14C...AT THIS POINT WILL KEEP MOST OF THE CWA DRY THURSDAY WITH THE EXCEPTION BEING THURSDAY NIGHT ACROSS OUR NORTHERN BORDER WHERE RIDGE RIDING WAVE MAY SPARK CONVECTION. FOR LATE WEEK AND THE WEEKEND...FORECAST CONFIDENCE IS NOT QUITE THERE YET AS THE FINER DETAILS OF HOW THE WESTERN CONUS TROUGH WILL PLAY OUT ARE STILL AN ENIGMA. IN THE SYNOPTIC SCALE THERE REMAINS GOOD AGREEMENT OF A FAIRLY STRONG TROUGH ADVANCING INTO THE NORTHERN ROCKIES WITH MOST OF THE FAVORABLE UPPER LEVEL ENERGY TARGETING THE NORTHERN PLAINS. SOLID MOISTURE RETURN AND WARMING TEMPERATURES WILL BE IN PLACE ACROSS THE CENTRAL PLAINS...WITH A FRONTAL PASSAGE/SFC TROUGH FOR THE WEEKEND. STORMS...POSSIBLY SEVERE WILL ONCE AGAIN BE POSSIBLE....BUT WITH LACKING CONSISTENCY...WILL CAP POP CHANCES AT 40 PERCENT OR LESS THROUGH THE WEEKEND. AS FOR TEMPERATURES...A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE END OF THE WORK WEEK...WITH HIGHS GENERALLY IN THE 80S...LOWS WILL BE SEASONAL IN THE 50 AND 60S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1246 PM CDT MON JUN 23 2014 GENERALLY VFR CONDITIONS FOR BOTH TAF SITES THROUGH THE PERIOD. THE USUAL CONVEATS EXISTS HOWEVER IN THE SUMMER CONVECTIVE SEASON WITH THE POSSIBILITY OF ISOLATED TSRA IN THE AREA. SHORT RANGE MODELS INCLUDING CAMS SUCH AS THE HRRR...CONTINUE TO INDICATE ISOLATED TSRA POTENTIAL MOVING FROM THE WRN SANDHILLS SEWD THIS AFTERNOON...MUCH LIKE YDAY. CURRENT CLOUD COVER ACROSS THE PANHANDLE INTO THE WRN SANDHILLS SUGGESTS BROAD CONVERGENCE THERE...BUT NOTHING FOCUSED AND THIS IS CONFIRMED IN SPC/LAPS MESO GUIDANCE. HAVE LEFT ANY MENTION OUT FOR THE AFTERNOON OF TAFS DUE TO LOW CONFIDENCE IN ANY PARTICULAR MODEL SOLUTION...AND LIMITED COVERAGE SHOULD SOMETHING DEVELOP. OF GREATER INTEREST WOULD BE THE EVOLUTION OF A CONVECTIVE SYSTEM MOVING OUT OF THE CO FRONT RANGE LATER THIS EVENING AND POSSIBLY AFFECTING THE KLBF TAF IN THE 05-12Z TIME FRAME. AGAIN HAVE LEFT MENTION OF PRECIP OUT FOR NOW AS MOST SHORT TERM MODELS TAKE THE SYSTEM INTO NWRN KS...THOUGH A MID LEVEL CIG WILL BE POSSIBLE WITH SUCH A SOLUTION. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JWS SHORT TERM...CDC LONG TERM...JACOBS AVIATION...JWS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1149 AM CDT MON JUN 23 2014 .UPDATE... ISSUED AT 1148 AM CDT MON JUN 23 2014 UPDATE TO FURTHER REFINE PRECIP CHANCES THROUGH THE AFTERNOON. WITH VERY SUBTLE FORCING AND LOW LEVEL MOISTURE LIMITED...COVERAGE SHOULD ALSO BE LIMITED. BROAD AREA OF SC HAS DEVELOPED ACROSS THE PORTIONS OF THE SANDHILLS WHICH MAY HAVE A LIMITING FACTOR ON HOW FAST TEMPS RISE THIS AFTERNOON. BELIEVE MODELS PICKING UP ON THIS AREA AS LOCATION OF SHRA/TSRA BUT LITTLE VERTICAL DEVELOPMENT NOTED ON VISIBLE SAT PICS AT THIS TIME...AND MID LEVEL LAPSE RATES ARE NOT CONDUCIVE YET FOR THAT. HIGHER TERRAIN FURTHER WEST SHOULD BE THE INITIATION FOR TSRA DEVELOPMENT LATER THIS AFTERNOON AND CONFIDENCE IS LOW THAT MUCH WILL ENTER THE FORECAST AREA UNTIL LATER THIS EVENING...AFTER A MORE ORGANIZED CONVECTIVE SYSTEM EMERGES FROM NERN CO AND MOVES EWD. UPDATE ISSUED AT 929 AM CDT MON JUN 23 2014 AS MCS CONTINUES TO WEAKEN AND MOVE OUT CI SHIELD ALSO PROGRESSING EWD. VISIBLE SAT PICS INDICATING POCKETS OF ELEVATED INSTABILITY IN THE FORM OF ENHANCEMENT OF AC LIKELY ON LEFTOVER BOUNDARIES. SHORT TERM MODELS CONTINUE TO SHOW SOME THREAT OF ISOLD SHOWERS AND MAYBE A COUPLE TSRA THROUGH THE MORNING INTO EARLY AFTERNOON LIKELY AS RESULT OF LOCAL CONVERGENCE ENHANCEMENT AS SUBTLE UPPER PV ANOMALY MOVES OUT OF SRN WY. WILL HAVE TO INVESTIGATE THIS A BIT MORE FOR THE AFTERNOON IN ORDER TO FURTHER REFINE BEST PRECIP CHANCES. OTHERWISE TEMPS AND DEW POINTS LOOK ON TRACK FOR NOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 319 AM CDT MON JUN 23 2014 ANOTHER MCS SHOULD DROP THROUGH THE CNTL HIGH PLAINS THIS AFTN. THE FORECAST USES 50 PERCENT OF THE RAP MODEL AND 50 PERCENT OF THE OTHER MODELS. THE ONGOING MCS APPEARS TO BE TAKING ON A CYCLONIC ROTATION WITH THE WARM SECTOR ACROSS SCNTL NEB AND THE UPPER LEVEL COLD POOL ACROSS SWRN NEB ATTM. RADAR TRENDS SUGGEST THIS SYSTEM COULD ROTATE THROUGH SCNTL NEB THIS MORNING AND SHOWERS AND TSTMS ARE POPPING LEFT AND RIGHT BETWEEN KLBF AND KLXN. FOR TONIGHT...NEBULOUS POPS ARE IN THE FCST ACROSS THE SANDHILLS AND AREAS SOUTH. GIVEN THE INABILITY OF THE SYNOPTIC SCALE MODELS TO PREDICT NOCTURNAL RAIN EVENTS OF LATE...THE FCST IS FORCED TO MAINTAIN A SCATTERED POP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 319 AM CDT MON JUN 23 2014 12Z TUESDAY AND BEYOND. NEAR DAILY PRECIPITATION CHANCES TO HEADLINE THE EXTENDED DISCUSSION THROUGH AT LEAST SATURDAY AS THE ACTIVE PATTERN CONTINUES. A BRIEF PERIOD OF NORTHWEST FLOW ALOFT WILL DIRECT TWO SUBTLE DISTURBANCES ACROSS THE CENTRAL PLAINS TUESDAY INTO WEDNESDAY. THE FIRST OF WHICH SHOULD BE EAST OF THE CWA BY 12Z TUESDAY. THERE REMAINS GOOD CONSENSUS HOWEVER THAT THUNDER CHANCES REMAIN THROUGH MUCH THE DAY AS THE NEXT DISTURBANCE FOLLOWS. THE ATMOSPHERE WILL CHARACTERIZED AS MODERATELY UNSTABLE...WITH GENERALLY 25-40 KTS OF DEEP LAYER SHEAR. STRONG TO SEVERE STORMS ARE ANTICIPATED...BUT POSSIBLY THE GREATER IMPACT WILL BE HEAVY RAINFALL POTENTIAL AS THERE/S SUPPORT OF ONE OR MORE MCS/S PASSING THROUGH THE SANDHILLS REGION. STORM MOTION WILL BE ON THE SLOW SIDE...GENERALLY LESS THAN 20KTS...AND WITH PWATS INCREASING OVER AN INCH AND A THIRD...RAINFALL RATES OF AN INCH OR TWO AN HOUR WILL BE POSSIBLE. UPPER LOW PRESSURE TO BUILD EAST INTO THE PACIFIC NORTHWEST WEDNESDAY ALLOWING THE EASTWARD DEVELOPMENT OF A LOW AMPLITUDE TRANSITORY RIDGE. PRECIPITATION CHANCES CONTINUE ON WEDNESDAY AS THE NEXT WAVE EMBEDDED IN THE NOW QUASI-ZONAL FLOW IMPACTS THE REGION. TIMING AND PLACEMENT OF THE BETTER PRECIPITATION CHANCES WILL BE GENERALLY TIED TO THE LOCATION OF A LOW LEVEL FRONTAL BOUNDARY AND HOW CONVECTION FROM THE PREVIOUS DAY PLAYS OUT. AT THIS TIME THE MODELS ARE FAVORING NORTHERN NEBRASKA WITH THE HIGHER POP CHANCES /40 PERCENT/ WEDNESDAY AFTERNOON...WILL FOLLOW SUIT WITH THE FORECAST. THE AFOREMENTIONED RIDGE MAY EFFECTIVELY CAP THE REGION ON THURSDAY AS MIDLEVEL TEMPS WARM AOA 14C...AT THIS POINT WILL KEEP MOST OF THE CWA DRY THURSDAY WITH THE EXCEPTION BEING THURSDAY NIGHT ACROSS OUR NORTHERN BORDER WHERE RIDGE RIDING WAVE MAY SPARK CONVECTION. FOR LATE WEEK AND THE WEEKEND...FORECAST CONFIDENCE IS NOT QUITE THERE YET AS THE FINER DETAILS OF HOW THE WESTERN CONUS TROUGH WILL PLAY OUT ARE STILL AN ENIGMA. IN THE SYNOPTIC SCALE THERE REMAINS GOOD AGREEMENT OF A FAIRLY STRONG TROUGH ADVANCING INTO THE NORTHERN ROCKIES WITH MOST OF THE FAVORABLE UPPER LEVEL ENERGY TARGETING THE NORTHERN PLAINS. SOLID MOISTURE RETURN AND WARMING TEMPERATURES WILL BE IN PLACE ACROSS THE CENTRAL PLAINS...WITH A FRONTAL PASSAGE/SFC TROUGH FOR THE WEEKEND. STORMS...POSSIBLY SEVERE WILL ONCE AGAIN BE POSSIBLE....BUT WITH LACKING CONSISTENCY...WILL CAP POP CHANCES AT 40 PERCENT OR LESS THROUGH THE WEEKEND. AS FOR TEMPERATURES...A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE END OF THE WORK WEEK...WITH HIGHS GENERALLY IN THE 80S...LOWS WILL BE SEASONAL IN THE 50 AND 60S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 611 AM CDT MON JUN 23 2014 VFR IS EXPECTED EAST OF HIGHWAY 83 TODAY. SCATTERED TSTM ACTIVITY IS EXPECTED WEST OF HIGHWAY 83...MAINLY FROM 18Z ONWARD AS STORMS DEVELOP NORTH AND MOVE SOUTH. TONIGHT...THE FORECAST IS UNCERTAIN AS THE MODELS SUGGEST A SECOND AREA OF TSTMS WILL DEVELOP ACROSS THE CNTL SANDHILLS AND CONTINUE THROUGHOUT THE NIGHT. LATER FORECASTS USING THE RAP MODEL WILL HOPEFULLY CLARIFY THIS AS THE SYNOPTIC SCALE MODELS HAVE SHOWN POOR SKILL FORECASTING STORM DEVELOPMENT LATELY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JWS SHORT TERM...CDC LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1241 PM CDT MON JUN 23 2014 .SYNOPSIS... ISSUED AT 324 AM CDT MON JUN 23 2014 REX BLOCKING OVER THE CANADIAN PRAIRIE IS FORECAST TO BREAK DOWN ON WEDNESDAY...BUT THERE IS GOOD AGREEMENT THAT THE NORTHEAST PACIFIC UPPER LEVEL LOW WILL BROADEN FURTHER INTO NORTHWESTERN CONUS...AND EVENTUALLY INTO THE NORTHERN PLAINS. SCATTERED SHOWERS AND THUNDERSTORMS WILL TRANSITION TO HIGHER CHANCES OF THUNDERSTORMS AS SOUTHWESTERLY FLOW ALOFT MOVES OVER THE DAKOTAS LATER THIS WEEK. && .UPDATE... ISSUED AT 1231 PM CDT MON JUN 23 2014 SHOWERS CONTINUE TO DEVELOP OVER NORTHERN NORTH DAKOTA IN CYCLONIC FLOW. FOR EARLY AFTERNOON UPDATE HAVE BUMPED UP POPS OVER THE NORTHERN TIER AS COVERAGE CONTINUES TO INCREASE AND HAVE PULLED POPS SOUTH A BIT FURTHER. UPDATES HAVE BEEN SENT. UPDATE ISSUED AT 841 AM CDT MON JUN 23 2014 CURRENT FORECAST REMAINS IN PRETTY GOOD SHAPE WITH UPPER LOW/TROF NEAR LAKE WINNIPEG CONTINUING TO SAG TO THE SOUTHEAST WHILE COOL FRONT WORKS ITS WAY INTO THE AREA. STILL EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP FROM NORTH TO SOUTH TODAY AS THESE FEATURES WORK THEIR WAY INTO THE STATE. UPDATE ISSUED AT 639 AM CDT MON JUN 23 2014 CYCLONIC FLOW ALOFT WITH SHORTWAVE TROUGH MOVING THROUGH SOUTHWEST NORTH DAKOTA. THIS GENERATING HIGH CLOUDS AND SOME VIRGA WITH NO PRECIP SO FAR REACHING THE GROUND. OTHERWISE MAIN FEATURE TODAY WILL BE THE UPPER LEVEL OW ACROSS SOUTHERN CANADA WHICH WILL MOVE SOUTH TODAY AND TONIGHT BRINGING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT MON JUN 23 2014 SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST TODAY WITH PEAK HEATING...BUT THERE IS UNCERTAINTY ABOUT HOW MUCH INSTABILITY WILL DEVELOP. THE MOST RECENT TWO HRRR RUNS HAVE INCREASED THEIR COVERAGE OF THUNDERSTORMS EMBEDDED WITHIN RAIN SHOWERS. CAPPED THE COVERAGE OF THUNDERSTORMS TO SCATTERED FOR TODAY AND TONIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 324 AM CDT MON JUN 23 2014 JUST A REMNANT OF THE PERSISTENT UPPER LOW WILL REMAIN ACROSS NORTH DAKOTA ON TUESDAY. THIS UPPER FEATURE ACCOMPANIED BY AN ASSOCIATED SURFACE FRONTAL BOUNDARY WILL HELP FOCUS SHOWERS AND SCATTERED THUNDERSTORMS ACROSS THE CENTRAL AND NORTH TUESDAY AFTERNOON. TUESDAY NIGHT ACTIVITY WILL BE MINIMAL AS THE COLD FRONT REMAINS SOUTH OF THE STATE...BECOMING STATIONARY...TO RETURN EVENTUALLY WEDNESDAY NIGHT AND THURSDAY AS A WARM FRONTAL BOUNDARY IN ADVANCE OF A WESTERN UPPER TROUGH. THIS H500 TROUGH AND SURFACE WARM FRONT WILL BE THE FOCUS FOR AN ACTIVE THUNDERSTORM PERIOD THURSDAY NIGHT INTO FRIDAY NIGHT. MODELS SUGGEST SEVERAL MCS TYPE SYSTEMS SPREADING THUNDERSTORMS INTO THE REGION AND WILL BE MONITORING THE POTENTIAL FOR MODERATE TO HEAVY RAIN DURING THIS TIME FRAME. POPS REMAIN LIKELY FRIDAY NIGHT INTO SATURDAY FOR THIS. POPS TRAIL OFF INTO 20 TO 30S SUNDAY AFTER THE PASSAGE OF THE SHORTWAVE TROUGH/COLD FRONT. TEMPERATURES DURING THE EXTENDED LOOK NEAR OR SLIGHTLY BELOW NORMAL WITH HIGHS IN THE 70S TO AROUND 80. LOWS IN THE 50S TO NEAR 60. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1231 PM CDT MON JUN 23 2014 SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE TO SPREAD FROM NORTH TO SOUTH OVER THE AREA TODAY...BRINGING LCL MVFR CIGS. TONIGHT...SOME AREAS OF FOG MAY DEVELOP PARTICULARLY OVER NORTHERN NORTH DAKOTA WHERE AREAS OF IFR CONDITIONS ARE EXPECTED AFFECTING THE KISN AND KMOT TERMINALS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJS SYNOPSIS...SCHECK SHORT TERM...SCHECK LONG TERM...WAA AVIATION...JJS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
402 PM EDT MON JUN 23 2014 .SYNOPSIS... MUGGY AIR DOMINATES. CONVECTION COVERAGE INCREASES TUESDAY AFTERNOON AND TUESDAY NIGHT...AS A COLD FRONT APPROACHES. FRONT CREEPS THROUGH DURING WEDNESDAY. DRIER AND MORE STABLE AIR EXPECTED THURSDAY. && .NEAR TERM /THROUGH TUESDAY/... DECENT FIELD OF CUMULUS ACROSS THE FORECAST AREA THIS AFTERNOON WITH CLOUDS EXPANDING IN AREAL COVERAGE. CLOUDS HAVE BEEN CAPPED SO FAR...BUT THERE MAY BE ENOUGH UPDRAFT STRENGTH TO KICK OFF A FEW SHOWERS...ESPECIALLY OVER THE MOUNTAINS. KEEPING ISOLD ACTIVITY GOING FOR NOW...AND WILL ALLOW FOR A CONTINUATION OF ISOLD POPS INTO THIS EVENING. LATEST RUC HINTS AT A WEAK SHORTWAVE AT THE MID LEVELS OVER NORTHERN WV WHICH STILL MAY ACT AS A TRIGGER INTO THE EVENING HOURS. MOISTURE INCREASES LATE TONIGHT AS QUASI STATIONARY FRONT SLIDES SLOWLY EASTWARD FROM CENTRAL KY. CONTINUED TREND OF RAMPING UP POPS LATE IN THE PERIOD. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... PRECIPITABLE WATER MAXES OUT 1.8 TO 2 INCHES OVERNIGHT TUESDAY NIGHT BEFORE LOWERING WEDNESDAY AFTERNOON AND EVENING. THE MAIN MID LEVEL SUPPORT LIFTS NORTHEAST THROUGH NORTHERN OHIO INTO WESTERN NEW YORK BY 12Z WEDNESDAY. WEAKER 500 MB SUPPORT...WITH THE WEAKENING TROF SWINGS THROUGH OUR CWA AFTER 06Z WEDNESDAY. SO MID LEVEL SUPPORT ARRIVES WELL AFTER MAXIMUM HEATING. WAS A BIT SLOWER TUESDAY EVENING...TRYING TO INCREASE POPS ACROSS SOUTHERN AND EASTERN COUNTIES. STILL QUESTIONABLE ON COVERAGE ACROSS EXTREME SOUTHERN WEST VIRGINIA INTO SOUTHWEST VIRGINIA OVERNIGHT TUESDAY NIGHT. WILL HOLD SOME HIGHER LIKELY POPS LONGER WEDNESDAY MORNING IN MANY COUNTIES FROM I-79 EAST. THOUGH...ON WEDNESDAY THE COVERAGE OF THUNDER FORECAST TO BE LESS WITH ABUNDANT CLOUDS EXPECTED. 700 MB STEERING FLOW IS ABOUT 20 KNOTS ON BOTH SIDE OF THIS TROF. YET...WILL CONSIDER ADDING A HAZARD TO THE HAZARDOUS WEATHER POTENTIAL TO A PORTION OF OUR CWA...FOR KEEPING AN EYE ON RAIN AMOUNTS AND SMALL STREAM FLASH FLOODING. THERE MAY BE SOME FOG DEVELOPING FOR 06Z TO 12Z THURSDAY...BUT CLOUDS AND LOW STRATUS MAY HINDER THICK SURFACE FOG. SO DID NOT INCLUDE THICK FOG IN WEATHER GRIDS AT THIS DISTANCE. BASED ON FORECAST SOUNDINGS...REMOVED POPS ON THURSDAY AND THURSDAY NIGHT...BUT NOT SURE HOW MUCH THE SURFACE DEW POINT WILL LOWER. HAVE 60 TO 65 DEW POINTS FORECAST NOW IN THE AFTERNOON. && .LONG TERM /FRIDAY THROUGH MONDAY/... ANOTHER WEAKENING MID LEVEL TROF EXPECTED TO BE LIFTING NORTHEAST IN THE LOWER OHIO VALLEY INTO THE MIDWEST ON FRIDAY INTO SATURDAY. STILL QUESTIONABLE ABOUT THE COVERAGE OF CONVECTION ASSOCIATED WITH IT...SO NO LIKELY POPS. WAS SLOWER TRYING TO INCREASE POPS ACROSS NORTHERN AND EASTERN COUNTIES ON FRIDAY. OVERALL THOUGH...500 MB HEIGHTS WILL BE BUILDING FOR THOSE LAST FEW DAYS OF JUNE. AS A RESULT...WENT A FEW DEGREES HIGHER THAN WPC MAXIMUM TEMPERATURE GUIDANCE FOR SUNDAY AND MONDAY. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... FIELD OF CU NOTED ON THIS AFTERNOONS SATELLITE IMAGERY WILL CONTINUE TO EXPAND IN AREAL COVERAGE. DAYTIME HEATING MAY BE ENOUGH TO CAUSE A FEW UPDRAFTS TO BREAK THE CAP TO ALLOW FOR ISOLD CONVECTION. OTHERWISE VFR CONDITIONS EXPECTED THROUGH THIS EVENING. SOME BL DECOUPLING WILL ALLOW FOR SOME FOG DEVELOPMENT ALONG RIVERS AND IN VALLEYS. EXPECT COVERAGE AND DENSITY OF FOG TO BE DOWN FROM PAST SEVERAL NIGHTS DUE TO INCREASE IN CLOUDS AND GRADIENT FLOW. CAN NOT RULE OUT DEVELOPMENT ENTIRELY THOUGH. INCREASING MOISTURE BY 12Z TIME FRAME WITH FRONT INCHING CLOSER FROM THE WEST WILL HELP LEAD TO AN UPSWING IN CONVECTION TOWARD END OF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND COVERAGE OF SHOWERS AND STORMS MAY NEED PREVAILING OR TEMPO IN THE TAF. 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 H H H H H H H H H M HTS CONSISTENCY H H H H H H H H H H H M BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H M M M H L PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z TUESDAY... IFR POSSIBLE IN SHOWERS/THUNDERSTORMS WEDNESDAY WITH STRATUS/FOG AT WEDNESDAY NIGHT INTO THURSDAY MORNING FOR SITES RECEIVING RAIN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KMC/KTB NEAR TERM...KMC SHORT TERM...KTB LONG TERM...KTB AVIATION...KMC/KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
152 PM EDT MON JUN 23 2014 .SYNOPSIS... CONVECTION CHANCES INCREASE SLOWLY THROUGH TUESDAY AS A COLD FRONT APPROACHES AND ARRIVES WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY/... DECENT FIELD OF CUMULUS ACROSS THE FORECAST AREA THIS AFTERNOON WITH CLOUDS EXPANDING IN AREAL COVERAGE. CLOUDS HAVE BEEN CAPPED SO FAR...BUT THERE MAY BE ENOUGH UPDRAFT STRENGTH TO KICK OFF A FEW SHOWERS...ESPECIALLY OVER THE MOUNTAINS. KEEPING ISOLD ACTIVITY GOING FOR NOW...AND WILL ALLOW FOR A CONTINUATION OF ISOLD POPS INTO THIS EVENING. LATEST RUC HINTS AT A WEAK SHORTWAVE AT THE MID LEVELS OVER NORTHERN WV WHICH STILL MAY ACT AS A TRIGGER INTO THE EVENING HOURS. MOISTURE INCREASES LATE TONIGHT AS QUASI STATIONARY FRONT SLIDES SLOWLY EASTWARD FROM CENTRAL KY. CONTINUED TREND OF RAMPING UP POPS LATE IN THE PERIOD. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... A VERY WARM AND HUMID AIRMASS...AND A VIGOROUS LEAD SHORT WAVE AHEAD OF AN APPROACHING COLD FRONT...WILL ACT TO BRING WIDESPREAD SHOWERS AND THUNDERSTORMS MAINLY TUESDAY AFTERNOON AND TUESDAY NIGHT. MODELS AGREE PRETTY WELL ON THE TIMING OF THE LEAD WAVE AND GOOD PROSPECTS FOR RAIN. TEMPERATURES WILL NOT BE AS HIGH TUESDAY DUE TO THE CLOUDS AND SHOWERS...BUT SHOULD STILL REACH THE LOWER TO MID 80S...AND IT WILL REMAIN QUITE HUMID. TEMPS TUESDAY NIGHT WILL BE WARM WITH TEMPERATURES STRUGGLING TO DROP BELOW 70. AS FAR AS THE FRONT IS CONCERNED...MODELS DIFFER ON WHETHER THE FRONT IS STRONG ENOUGH TO ACTUALLY MOVE EASTWARD ACROSS THE AREA BEHIND THE SHORT WAVE...AS FLOW ALOFT TURNS MORE WESTERLY OR NORTHWESTERLY. THE GFS AND CMC MODELS MANAGE TO DRIVE THE FRONT EAST OF THE AREA LATER WEDNESDAY...WITH THE NAM AND EURO MODELS SLOWLY DISSIPATING THE FRONT AS IT MOVE INTO THE AREA WEDNESDAY. IT WILL...IN ANY CASE...LAG BEHIND THE MAIN SHORT WAVE WHICH DEPARTS WEDNESDAY MORNING. DESPITE MUCH OF THE UPPER DYNAMICS DEPARTING WITH THE SHORT WAVE...AND WHETHER THE FRONT MAKES IT OR DISSIPATES...THERE WILL BE A WARM AND HUMID AIRMASS AHEAD OF THE FRONT TO CONTINUE A CHANCE OF SHOWERS AND STORMS WEDNESDAY. THEREAFTER...ENOUGH DRIER AIR ALOFT FINALLY MOVES IN FOR THURSDAY AND MUCH OF FRIDAY TO MAKE MOST OF THE AREA RAIN FREE. WHETHER THE FRONT MAKES IT OR NOT...THERE WILL NOT BE MUCH OF A TEMPERATURE DIFFERENCE FOR HIGHS..WITH TEMPS STILL REACHING INTO THE 80S. && .LONG TERM /FRIDAY THROUGH SUNDAY/... A SOMEWHAT TYPICAL LATE-JUNE PATTERN WILL CONTINUE IN THE EXTENDED PERIOD...CHARACTERIZED BY WARM AND MUGGY DAYS WITH AT LEAST A SLIGHT CHANCE OF A SHOWER AND/OR THUNDERSTORM EVERY DAY. HIGHER CHANCES OF PRECIP ARE CENTERED ON TWO DISTURBANCES...ONE ON FRIDAY AND THE OTHER NEAR WEEKEND/S END INTO SUNDAY NIGHT/EARLY MON. AFOREMENTIONED TEMPERATURES WILL BE NEAR SEASONAL...WITH NO REAL HEAT WAVES OR COOL PERIODS FORESEEN. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... FIELD OF CU NOTED ON THIS AFTERNOONS SATELLITE IMAGERY WILL CONTINUE TO EXPAND IN AREAL COVERAGE. DAYTIME HEATING MAY BE ENOUGH TO CAUSE A FEW UPDRAFTS TO BREAK THE CAP TO ALLOW FOR ISOLD CONVECTION. OTHERWISE VFR CONDITIONS EXPECTED THROUGH THIS EVENING. SOME BL DECOUPLING WILL ALLOW FOR SOME FOG DEVELOPMENT ALONG RIVERS AND IN VALLEYS. EXPECT COVERAGE AND DENSITY OF FOG TO BE DOWN FROM PAST SEVERAL NIGHTS DUE TO INCREASE IN CLOUDS AND GRADIENT FLOW. CAN NOT RULE OUT DEVELOPMENT ENTIRELY THOUGH. INCREASING MOISTURE BY 12Z TIME FRAME WITH FRONT INCHING CLOSER FROM THE WEST WILL HELP LEAD TO AN UPSWING IN CONVECTION TOWARD END OF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND COVERAGE OF SHOWERS AND STORMS MAY NEED PREVAILING OR TEMPO IN THE TAF. 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 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H M M M BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H M M M L PKB CONSISTENCY H H H H H H M M M M M M CKB CONSISTENCY H H H H H H M H H H H H AFTER 18Z TUESDAY... IFR POSSIBLE IN IN THUNDERSTORMS WEDNESDAY WITH STRATUS/FOG AT NIGHT FOR SITES RECEIVING RAIN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JMV/26 NEAR TERM...KMC SHORT TERM...JMV LONG TERM...50 AVIATION...KMC
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
102 PM CDT MON JUN 23 2014 .DISCUSSION... 18Z AVIATION DISCUSSION BELOW. && .AVIATION... WIDELY SCATTERED SHOWERS...WITH LOCALLY HEAVY RAIN...AND EMBEDDED ISOLATED THUNDERSTORMS WEST OF METRO MOVING UP AHEAD OUT A LINE OF SHOWERS CREATED UPON NORTH CENTRAL TEXAS CONVECTIVE OUTFLOW NOW PASSING OVER THE NORTHERN TERMINAL AIR SPACE OF KCLL AND KUTS. SHORT TERM FORECAST CALLS FOR VCSH WITH TEMPO THUNDER...IFR CONDITIONS WITHIN HEAVIEST RAIN OR STORM CELLS. CURRENTLY...BULK OF LIGHTNING CONCENTRATED OVER THE NORTHERN FORT BEND AND WESTERN HARRIS COUNTIES. LEAVING VCSH IN THROUGH EARLY EVENING TO ACCOUNT FOR THE POSSIBLE PASSAGE OF A WEAK SHORTWAVE DISTURBANCE. MODELS HAVE BEEN OF NO GUIDANCE SO CONFIDENCE IS EXTREMELY LOW WITH THIS PACKAGE. AS OF NOW...WITH LITTLE TO NO CHANGE IN THE LARGE SCALE ENVIRONMENT...THE ONLY LULL WILL BE TONIGHT (DUE TO THE RECENT WORK OVER AND LACK OF HEATING) WITH AN ANTICIPATED RETURN OF SHOWER/ISOL THUNDER ACTIVITY TOMORROW MORNING AS TEMPERATURES WARM INTO THE MIDDLE 80S. 31 && .PREV DISCUSSION... /ISSUED 1141 AM CDT MON JUN 23 2014/ UPDATE... INCREASED POPS TODAY. DISCUSSION... CONVECTION HOLDING TOGETHER AND EXPANDING IN COVERAGE. HAVE RAISED POPS TO LIKELY OVER THE NW TWO-THIRDS OF THE AREA. RAP 13 PERFORMING WELL AND HAVE LEANED TOWARD IT`S SOLUTION FOR THE REMAINDER OF THE DAY. OF INTEREST...THE RAP BRINGS A STRONG S/WV OVER THE CENTRAL PLAINS INTO NORTH TEXAS THIS EVENING AND BRINGS ANOTHER ROUND OF SHRA/TSRA INTO THE NORTHERN HALF OF THE CWA. THE NAM 12 SUPPORTS THIS SCENARIO AS WELL. 43 PREV DISCUSSION... /ISSUED 930 AM CDT MON JUN 23 2014/ UPDATE... SEE MORNING UPDATE. DISCUSSION... A STRONG OUTFLOW BOUNDARY IS HEADING SOUTH AND CONVECTION IS GETTING CLOSE TO THE NORTHERN PART OF THE CWA. SHORT TERM GUIDANCE STILL SUGGESTS WEAKENING OF THIS SYSTEM BUT THE RAP 13 AND TEXAS TECH 3 KM BECOMING MORE BULLISH WITH POPS OVER THE NW THIRD OF THE CWA. RAISED POPS TO CHANCE OVER THE NW ZONES. 12Z CRP SOUNDING HAS A PW VALUE OF 2.06 INCHES WITH SOME DRY AIR AT 700 MB. THE CONVECTIVE TEMPS ARE IN THE MID 80S WHICH IS MORE THAN REACHABLE. SHORT TERM GUIDANCE SUGGESTS CONVECTION WILL WANE THIS AFTN AS SOME OF THE DRIER AIR ALOFT MIXES TO THE SURFACE. WILL RE-EVALUATE THAT TREND AFTER 17Z. 43 PREV DISCUSSION... /ISSUED 648 AM CDT MON JUN 23 2014/ DISCUSSION... UPDATED AVIATION SECTION. AVIATION... LATEST RADAR COMPOSITES SHOW BAND OF STORMS SITUATED OVER NORTH TEXAS...NEAR THE DFW METROPLEX. LINE OF STORMS WAS MOVING SOUTHEAST AROUND 45 MPH. INFRARED SATELLITE SHOWING WARMING CLOUD TOPS AND OVERALL WEAKENING OF THIS CONVECTIVE COMPLEX. AVAILABLE MESO MODELS ARE NOT HANDLING THIS SYSTEM VERY WELL...BUT THESE ALSO SHOW A DISSIPATION OF THE LINE GOING FORWARD. TAFS ARE WRITTEN WITH THE IDEA THAT THIS DISSIPATING TREND WILL CONTINUE...BUT NOT COMPLETELY CERTAIN IT WILL OCCUR GIVEN FAIRLY UNSTABLE AIRMASS DOWNSTREAM. FOR THIS REASON HAVE GONE WITH A VCTS FOR CLL...UTS AND CXO BASED ON TIMING OF CURRENT LINE BUT BASED ON LOW PROBABILITY IT WILL SURVIVE AS A LINE. FARTHER SOUTH AND EAST...EVEN LESS LIKELY LINE WILL MAKE IT...AND WILL CONTINUE WITH NO MENTION OF PRECIP THERE IN THE TAFS. OTHERWISE EXPECT A DECREASE IN CONVECTION TONIGHT...WITH JUST SOME PATCHY MVFR LATE TONIGHT FOR IAH ON NORTH AND NORTHWEST. PREV DISCUSSION... /ISSUED 415 AM CDT MON JUN 23 2014/ DISCUSSION... REGIONAL SATELLITE IMAGERY AND RADAR SHOW MATURE SQUALL LINE PUSHING THROUGH OK/TX AND RED RIVER REGION. CLOSER TO HOUSTON MAINLY OBSERVING SPOTTY SHOWERS BUT NOT MUCH PRECIP HITTING THE GROUND. SQUALL LINE SHOULD CONTINUE TO PUSH SOUTH TOWARDS THE AREA THIS MORNING WITH STRONG COLD POOL BEHIND IT. RAPID REFRESH AND WRF RUNS SHOW THE SQUALL LINE BREAKING UP BEFORE REACHING COLLEGE STATION. KEPT THE FORECAST IN LINE WITH THIS THINKING FOR THE MORNING BUT CONCERNED LINE COULD PUSH FARTHER SOUTH THAN EXPECTED SINCE THERE IS LITTLE SUBSIDENCE AND DRY AIR TO IMPEDE ITS PROGRESS. FORECAST HOLDS WITH 20 POPS AS STILL POSSIBLE FOR ISO CONVECTION TO DEVELOP DURING THE HEAT OF THE DAY. WATER VAPOR IMAGERY AND 00Z 500MB ANALYSIS SHOW TROUGHING OVER MUCH OF TX. UPPER RIDGE IS NOT ALL THAT STRONG AND LIKELY SPLIT BETWEEN NORTHERN MEXICO AND THE C GULF. GLOBAL MODELS ALL SUPPORT TROUGHING OVER TX THROUGH THE END OF THE WEEK. MODELS ALSO SHOW A SURGE IN TROPICAL MOISTURE LATE TUE INTO WED. GIVEN PERCIP WATER VALUES OF NEAR 2 INCHES ACROSS MUCH OF THE AREA FOR WED/THUR DECIDED TO GO WITH 50/60 POPS EACH OF THOSE DAYS. TROPICAL MOISTURE WILL BE SUPPORTIVE OF 1-2 INCH AN HOUR RAINRATES IN STRONGER STORMS SO LOCALLY HEAVY RAINFALL A CONCERN. THIS COULD RESULT IN URBAN FLOODING AND RAPID INCREASES IN BAYOUS. AREAWIDE RAINFALL TOTALS OF 1 TO 2 INCHES OF RAIN WILL BE POSSIBLE FOR THE LATER HALF OF THE WEEK. THE TRICK TO THE FORECAST WILL BE WHERE THE ISOLATED 3 TO 5 INCH RAINFALL AMOUNTS SET UP WHICH COULD LEAD TO FLOODING IMPACTS. UPPER LEVEL RIDGING DOES TRY TO STRENGTHEN DEPENDING ON THE MODEL. THE ECMWF SEEMS TO BE MORE ROBUST WITH THE RIDGE SUNDAY INTO NEXT MONDAY. MEANWHILE THE GFS MAINTAINS A SHEAR AXIS OVER THE NW GULF. RIGHT NOW WILL STILL CARRY SOME LOWER POPS. THINK FRI/SAT WILL BE DRIER BUT 40 POPS STILL DECENT CHANCES. WILL ALSO KEEP 20 POPS IN THE FORECAST FOR SUN/MON AS THERE STILL SHOULD BE PLENTY OF DEEP MOISTURE IN PLACE AND RIDGING STRENGTH WILL STILL BE RELATIVELY UNKNOWN. TEMPERATURES SHOULD REMAIN NEAR NORMAL FOR THE COMING WEEK MAYBE A DEGREE OR TWO COOLER WITH THUNDERSTORM CHANCES. THIS MEANS UPPER 80S TO LOW 90S WITH MIN TEMPS IN THE MID 70S. STILL COULD GET SOME RAIN COOLED LOW 70S OR UPPER 60S BUT DIFFICULT TO FORECAST THOSE OCCURRENCES SINCE IT WILL DEPEND ON THE CONVECTION. THE NICE THING ABOUT THIS FORECAST IS THAT TEMPS SHOULD REMAIN BELOW 95F THROUGH ALMOST THE END OF JUNE. CLIMATE FACTOID...CLL/IAH/HOU HAVE YET TO REACH 95F OR HIGHER THIS YEAR FOR A MAX TEMP. 39 MARINE... LIGHT TO MODERATE ONSHORE FLOW WILL CONTINUE THE NEXT FEW DAYS WITH SUSTAINED 10 METER WINDS GENERALLY ONSHORE AROUND 10 TO 15 KNOTS THROUGH TUESDAY. GRADIENT IS FORECAST TO TIGHTEN SOMEWHAT MID TO LATE WEEK WITH SMALL CRAFT EXERCISE CAUTION WINDS A POSSIBILITY BY WED OR THU. WITH PERSISTENT SE FLOW AND LONG FETCH SEAS ARE EXPECTED TO GRADUALLY BUILD THROUGH THE WEEK...WITH 6 TO 9 FOOT SEAS A GOOD BET BY THURSDAY AND FRIDAY. 46 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 74 90 74 88 74 / 30 40 20 60 20 HOUSTON (IAH) 76 90 75 88 75 / 20 40 20 60 30 GALVESTON (GLS) 80 88 80 87 80 / 20 30 40 50 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...43 AVIATION/MARINE...31
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1227 PM CDT MON JUN 23 2014 .AVIATION... A COLD FRONT THAT EXTENDED SOUTHEAST OF A MCKINNEY /KTKI/ TO BRECKENRIDGE /KBKD/ LINE AT 17Z WILL CONTINUE TO MOVE SOUTHEAST AND SHOULD BE MOVING THROUGH THE METROPLEX TAF SITES AROUND 18Z...SO HAVE STARTED OFF THE WINDS AS NORTHWEST AT 10 KNOTS. WINDS SHOULD COME BACK AROUND TO THE SOUTHEAST AT 10 KNOTS OR LESS BEFORE SUNSET /01Z/. SOME BRIEF MVFR CEILINGS MAY MOVE INTO THE METROPLEX TAF SITES THIS AFTERNOON...SO HAVE PLACED A TEMPO BKN025 IN FOR THE 18-20Z PERIOD. WITH LIGHT WINDS OVERNIGHT AND A WET GROUND...SOME LIGHT FOG MAY DEVELOP TOWARD DAYBREAK. THUS HAVE PLACED 5SM BR IN THE METROPLEX TAFS FOR THE 12-15Z PERIOD. THIS WILL LIKELY BE ADDED TO WACO/S TAF WITH THE 21Z UPDATE. SCATTERED ELEVATED SHOWERS/THUNDERSTORMS COULD POP UP LATE AFTERNOON INTO THIS EVENING...BUT THE CHANCES AT THE INDIVIDUAL TAF SITES IS TOO LOW TO MENTION AT THIS TIME. LIKEWISE THERE WILL BE A CHANCE OF SHOWERS AND THUNDERSTORMS TUESDAY BUT THE CHANCES AT THE INDIVIDUAL TAF SITES ARE NOT HIGH ENOUGH TO INCLUDE IN THE TAFS AT THIS TIME. 58 && .UPDATE... THIS MORNINGS MCS CONTINUES TO WEAKEN OVER THE SOUTHERN COUNTIES OF THE CWA. THE MOVEMENT OF THE REMAINING SHOWERS AND STORMS IS TO THE EAST AND SOUTHEAST. AN OUTFLOW BOUNDARY CAN BE SEEN ON THE KGRK RADAR PUSHING AHEAD OF THE LEADING EDGE INTO THE HILL COUNTRY AND SOUTHEAST TEXAS. THIS OUTFLOW BOUNDARY WILL LIKELY NOT BE A FACTOR FOR AFTERNOON CONVECTION IN OUR CWA WITH THE BOUNDARY LOCATED SOUTH OF THE REGION AND THE MEAN STEERING FLOW TO THE SOUTHEAST. HOWEVER...ANOTHER BOUNDARY/FRONT CAN BE SEEN ON THE KFWS RADAR AND SURFACE OBS ACROSS OKLAHOMA AND NORTHWEST TEXAS... MOVING INTO THE NORTHWESTERN PORTIONS OF THE CWA. THE WINDS AT BOWIE HAVE COME AROUND TO THE NORTH AND OTHER SITES ALONG THE RED RIVER HAVE SHIFTED TO THE WEST. BOTH THE HRRR AND RAP ARE DEVELOPING CONVECTION ALONG THIS BOUNDARY EARLY THIS AFTERNOON WITH THE FOCUS FOR CONVECTION SLOWLY MOVING SOUTH THROUGH THE AFTERNOON HOURS. DESPITE THE PRESENCE OF THE BOUNDARY IN OUR NORTHWESTERN COUNTIES...THE AFTERNOON FORECAST IS STILL MUDDLED BY THIS MORNING/S MCS. SURFACE TEMPERATURES ACROSS MOST OF THE REGION ARE COOL IN THE UPPER 60S AND LOWER 70S. ANALYSIS OF AMDAR SOUNDINGS SHOW THE TEMPERATURES JUST ABOVE THE SURFACE HAVE RAPIDLY WARMED IN THE WAKE OF THE MCS DUE TO SUBSIDENCE ON THE BACK SIDE. A RECENT AMDAR SOUNDING FROM DFW AT 1555Z SHOWS TEMPERATURES AT 900 MB HAVE WARMED 9 DEGREES CELSIUS SINCE THE RAIN STARTED. IN ADDITION...THE LOWER LEVELS OF THE ATMOSPHERE HAVE SIGNFICANTLY DRIED UP TO ABOUT 600 MB. IN ORDER TO BREAK THE CAP THAT HAS DEVELOPED IN THE WAKE OF THE MCS...SURFACE TEMPERATURES WOULD HAVE TO WARM INTO THE MID AND UPPER 90S AND THAT IS NOT GOING TO HAPPEN TODAY. WHAT WE WILL LIKELY SEE IS ISOLATED TO SCATTERED ELEVATED CONVECTION DEVELOP WITH HELP FROM A SHORTWAVE MOVING NORTHWEST TO SOUTHEAST ACROSS PRIMARILY THE NORTHERN HALF OF THE REGION THIS AFTERNOON. IF THE ELEVATED CONVECTION IS ABLE TO SATURATE THE LOWER LEVELS OF THE ATMOSPHERE OVER TIME /AND THUS EFFECTIVELY COOL THE TEMPERATURES AROUND 900-800 MB/...IT IS POSSIBLE WE COULD HAVE SURFACE BASED CONVECTION LATER THIS AFTERNOON...IN PARTICULAR AROUND ANY BOUNDARIES OR THE FRONT. HOWEVER...CONFIDENCE IN SURFACE BASED CONVECTION IS RELATIVELY LOW FOR THE REMAINDER OF THE DAY. IN ANTICIPATION OF ELEVATED CONVECTION FOR THE REMAINDER OF THE DAY...TAILORED POPS TO 30 PERCENT IN THE EAST AND 40 PERCENT IN THE WEST. THE MODELS ARE INDICATING MUCH OF THE CONVECTION MAY OCCUR WEST OF INTERSTATE 35 WHERE THE CLOUDS ARE ALREADY THINNING OUT...SURFACE TEMPERATURES WILL BE THE WARMEST AND INSTABILITY WILL THUS BE THE HIGHEST IN THE AREA. WITH ANY STORMS TODAY...GUSTY WINDS...LIGHTNING...AND HEAVY RAINFALL WILL BE THE MAIN THREATS. STORM MOTION TODAY IS EXPECTED TO BE FASTER THAN THE LAST FEW DAYS WHICH SHOULD HELP MITIGATE ANY FLASH FLOOD THREAT THIS AFTERNOON BUT WITH A CONTINUED THREAT FOR HEAVY RAIN...WILL NEED TO CLOSELY MONITOR RADAR TRENDS. 82/JLD && .PREV DISCUSSION... /ISSUED 414 AM CDT MON JUN 23 2014/ THE PRIMARY WEATHER FEATURE OF INTEREST EARLY THIS MORNING WAS A SQUALL LINE LOCATED FROM NORMAN TO WICHITA FALLS TO LUBBOCK AS OF 4 AM CDT. THIS SQUALL LINE WAS A BIT WEAKER THAN IT WAS AROUND MIDNIGHT...HOWEVER ITS RADAR REFLECTIVITY STRUCTURE CONTINUED TO SHOW A WELL ORGANIZED LINEAR MCS WITH FAIRLY UPRIGHT UPDRAFTS AND STRONG CONVECTION ALONG THE LEADING EDGE OF ITS OUTFLOW BOUNDARY. THIS STRUCTURE LIKELY MEANS THAT THIS SQUALL LINE WILL NOT FALL APART OR SLOW DOWN MUCH AS IT CONTINUES SOUTHEAST OVER NORTH TEXAS EARLY THIS MORNING. THE PORTION OF THE SQUALL LINE THAT WILL LIKELY REACH OUR NORTHWESTERN CWA FIRST WAS STILL SEVERE WARNED BY WFO OUN AT THE TIME OF THIS DISCUSSION. KFDR RADAR OBSERVED A 50-54 KT INBOUND VELOCITY AT AROUND 100 FT AGL WITHIN THIS WARNING. THE SQUALL LINE MAY CONTINUE TO WEAKEN A BIT AS IT MOVES TOWARDS NORTH TEXAS...BUT STRONG TO DAMAGING WIND GUSTS WILL CERTAINLY BE A POSSIBILITY WITHIN THIS LINE THIS MORNING. AT THIS TIME...THE SQUALL LINE WAS ON TRACK TO MOVE THROUGH THE DFW METROPLEX FROM APPROXIMATELY 6 AM TO 8 AM. THIS TIMING MAY CHANGE AS INTENSITY CHANGES WITHIN THE LINE OF STORMS...HOWEVER IMPACTS TO THE MORNING RUSH HOUR COMMUTE LOOK LIKELY AT THIS TIME. ASIDE FROM STRONG WIND GUSTS...LOCALLY HEAVY RAINFALL IS EXPECTED TO BE A PROBLEM AS WELL. LOCALIZED FLOODING IS CONTINGENT UPON THE SPEED OF THE STORMS AND THE SQUALL LINE IN GENERAL THIS MORNING. THE TEXAS TECH WRF INDICATES THAT THE SQUALL LINE...OR ITS REMNANTS...WILL PUSH THROUGH THE ENTIRE CWA FROM 12 TO 18Z. IF THIS SCENARIO PANS OUT...LOCALIZED FLOODING IS LESS LIKELY BECAUSE STORMS WILL BE MOVING THROUGH THE AREA TOO QUICKLY. MANY OTHER HIGH-RESOLUTION GUIDANCE MEMBERS WEAKEN THE SQUALL LINE TO THE POINT THAT IT DROPS A NEARLY STATIONARY BOUNDARY NEAR OR JUST SOUTH OF INTERSTATE 20 BY LATE THIS MORNING. IF THIS OCCURS...IT`S ONLY GOING TO HAPPEN BECAUSE THE SQUALL LINE SLOWS DOWN CONSIDERABLY FROM ITS CURRENT PACE. ANY ONGOING RAIN SHOWER AND THUNDERSTORM ACTIVITY IN THIS SCENARIO WOULD BE MORE LIKELY TO PRODUCE LOCALIZED FLOODING AS STORMS WILL SIMPLY BE MOVING SLOWER. EITHER WAY...LOCALLY HEAVY RAIN WILL OCCUR WITH ANY THUNDERSTORM ACTIVITY ALONG THE SQUALL LINE BECAUSE MODELS INDICATE THAT PWATS ONLY INCREASE OUT AHEAD OF THE SQUALL LINE ACROSS NORTH TEXAS THIS MORNING. WITH LITTLE AIRCRAFT ACTIVITY (FOR AMDAR SOUNDINGS) OVERNIGHT...ITS DIFFICULT TO ESTABLISH IF THIS IS REALISTIC OR NOT. HOWEVER LOOKING AT THE GOES SOUNDER OUTPUT...THERE IS A PLUME OF 2 INCH (OBSERVED AS 50 MM) PWATS LOCATED JUST SOUTH OF THE DFW AREA...CONTINUING SOUTH OVER CENTRAL TEXAS. HOW FAR NORTH OR EAST THIS PLUME EXTENDS IS UNKNOWN BECAUSE THE SATELLITE CAN NOT SEE THROUGH THICK UPPER LEVEL CLOUDS OVER THESE AREAS. THE FACT THAT 2 INCH PWATS ARE OBSERVED TO THE SOUTHWEST OF WHERE MODELS DEPICT 2 INCH PWATS THIS MORNING (GENERALLY NORTH OF I-20 AND EAST OF I-35) IS A GOOD SIGN THAT THE MODELS PROBABLY HAVE THIS RIGHT. AS A RESULT...WENT AHEAD WITH A MENTION OF HEAVY RAINFALL IN THE WORDED FORECAST THIS MORNING...HIGHLIGHTING AREAS NORTH OF INTERSTATE 20 AS HAVING THE HIGHEST CHANCE AT SEEING LOCALLY HEAVY RAINS. IN REALITY...WE WILL JUST HAVE TO WATCH AND SEE HOW THE SQUALL LINE EVOLVES BECAUSE WHERE EVER THE STRONGEST THUNDERSTORM ACTIVITY GOES...THE HEAVY RAIN WILL FOLLOW SUIT. THE IMPACTS WERE NOT EXPECTED TO BE WIDESPREAD ENOUGH TO RESULT IN LARGE SCALE FLOODING...SO NO FLOOD WATCH WILL BE ISSUED WITH THIS FORECAST PACKAGE. WILL MONITOR STORMS AND HANDLE LOCALIZED FLOODING TACTICALLY VIA WARNINGS...GRAPHICS AND SOCIAL MEDIA DISSEMINATION. FOR THIS AFTERNOON...NEW THUNDERSTORM CHANCES REALLY DEPEND ON WHAT HAPPENS WITH OUR SQUALL LINE THIS MORNING. MANY MODELS SHOW A GOOD QPF SIGNAL IN LINE WITH THE SQUALL LINE...BUT MOST UNFORTUNATELY FAIL TO CARRY THE DYNAMICS OF THE SQUALL LINE INTO THE MODEL MASS FIELDS. FOR INSTANCE...NOT ONE OPERATIONAL MODEL BOTHERS TO BRING A WIND SHIFT LINE INTO THE CWA WITH THE SQUALL LINE QPF BLOB THIS MORNING. THESE MODELS ALSO FAIL TO SUFFICIENTLY STABILIZE/COOL THE LOWER TROPOSPHERE BEHIND THE SQUALL LINE. THIS PRESENTS A BIG FORECAST PROBLEM AS BOTH OF THESE FACTORS WILL PLAY A HUGE ROLE IN THUNDERSTORM CHANCES FOR THIS AFTERNOON. THE TEXAS TECH WRF AND THE 4 KM NAM BOTH AT LEAST INDICATED SOME RESPONSE IN THE LOW-LEVEL WIND FIELD...SO THESE MODELS WERE WEIGHED MORE HEAVILY FOR THIS AFTERNOON`S THUNDERSTORM FORECAST. AN 08Z OBJECTIVE SURFACE ANALYSIS INDICATED A THETA-E DROP OF AROUND 11 KELVIN BEHIND THE SQUALL LINE THIS MORNING. AS FAR AS COLD POOLS GO BEHIND SQUALL LINES...THIS IS NOT SUPER IMPRESSIVE...BUT WILL NOT SIMPLY DISSIPATE WITH A FEW HOURS OF DAYTIME HEATING EITHER. AS A RESULT...WHEREVER THE SQUALL LINE LEAVES AN OUTFLOW BOUNDARY THIS MORNING...IT IS LIKELY TO HANG AROUND AND MAINTAIN SOME IDENTITY FOR THIS AFTERNOON. AT THIS TIME...USING THE TEXAS TECH WRF`S SURFACE WIND FIELD AS A PROXY FOR THE OUTFLOW BOUNDARY`S LOCATION THIS AFTERNOON...THINK IT WILL END UP SOUTH OF INTERSTATE 20. AS A RESULT...WENT AHEAD AND LOWERED POPS FOR LOCATIONS NORTH OF THE INTERSTATE FOR THIS AFTERNOON FROM THE PREVIOUS FORECAST. IF THE SQUALL LINE ACTUALLY MOVES ALL THE WAY THROUGH CENTRAL TEXAS BY 18Z AS THE TEXAS TECH WRF REFLECTIVITY SUGGESTS...IT MAY COMPLETELY SHUT DOWN THUNDERSTORM CHANCES FOR THE CWA FOR THIS AFTERNOON. AS IT STANDS...HAVE 30 TO 40 POPS IN THE FORECAST SOUTH OF INTERSTATE 20 AND WEST OF INTERSTATE 35 FOR THIS AFTERNOON REPRESENTING THE MAXIMUM POPS ACROSS THE CWA. HIGHLIGHTED AREAS WEST OF INTERSTATE 35 BECAUSE MOST MODELS INDICATE THAT A WEAK SHORTWAVE TROUGH CURRENTLY LOCATED ALONG THE ARIZONA/MEXICO BORDER WILL MOVE EAST AND PROVIDE SOME FORCING FOR ASCENT OVER WEST- CENTRAL TEXAS BY 00Z TODAY. IF THERE REALLY IS AN OUTFLOW BOUNDARY STALLED OUT IN PLACE HERE...THE WEAK FORCING FOR ASCENT FROM THIS TROUGH COMBINED WITH THE BOUNDARY SHOULD BE AN IDEAL PLACE FOR NEW THUNDERSTORMS TO DEVELOP BY LATE THIS AFTERNOON. AS MENTIONED ABOVE...IF THE OUTFLOW BOUNDARY IS ELSEWHERE BY THIS AFTERNOON...POPS WILL NEED TO BE ADJUSTED ACCORDINGLY. THE 4 KM NAM INDICATES THAT THIS BOUNDARY IS VERY IMPORTANT FOR THIS AFTERNOON STORMS AS IT BLOWS UP SEVERAL CLUSTERS OF VERY STRONG LOOKING CONVECTION ALONG THIS BOUNDARY BY 00Z. THE NSSL WRF ON THE OTHER HAND INDICATES THAT THE OUTFLOW BOUNDARY WILL NOT BE AS IMPORTANT AS AN MCV WITH REGARDS TO AFTERNOON THUNDERSTORM CHANCES. THIS MODEL KEEPS WELL DEFINED MCV IN PLACE OVER EAST CENTRAL OKLAHOMA THIS AFTERNOON AND CONCENTRATES THUNDERSTORM ACTIVITY THERE INSTEAD OF ALONG THE OUTFLOW BOUNDARY OVER NORTH/CENTRAL TEXAS. IT IS DIFFICULT TO KNOW WHAT WILL BE IMPORTANT UNTIL THIS MORNINGS SQUALL LINE DISSIPATES AND WE CAN REEVALUATE WHAT THE THERMODYNAMIC AND KINEMATIC ENVIRONMENT LOOKS LIKE AT THAT TIME. FOR TONIGHT...MOST MODELS INDICATE THAT OUR OUTFLOW BOUNDARY WILL LIFT NORTH TO THE RED RIVER AND BECOME THE FOCUS FOR NEW THUNDERSTORM ACTIVITY OVERNIGHT. WENT AHEAD AND KEPT HIGHER POPS OVER THE NORTHERN CWA FOR TONIGHT AS A RESULT. IF THE OUTFLOW BOUNDARY MAINTAINS ANY IDENTITY THROUGHOUT THE AFTERNOON HOURS OF THE DAY...IT WILL PROBABLY SERVE TO ENHANCE THE SLOPE OF LOW- LEVEL ISENTROPIC SURFACES PERPENDICULAR TO LOW-LEVEL WINDS RESULTING IN ENHANCED LIFT. THE NORTHERN CWA SHOULD BENEFIT FROM THIS ENHANCED LOW-LEVEL LIFT MORE SO THAN THE SOUTH. TUESDAY THROUGH THURSDAY...MORE MODELS ARE SHOWING THAT A COL IN THE UPPER LEVEL FLOW FIELD WILL SET UP OVER NORTH TEXAS DURING THIS TIME FRAME. AS A RESULT...KEPT BROAD BRUSHED POPS IN PLACE FOR ALL AREAS. HAVE SLIGHTLY HIGHER POPS ADVERTISED DURING THE AFTERNOON HOURS OF THE DAY EACH DAY AS ANY HEATING COMBINED WITH ANY WEAK UPPER TROUGH ALOFT WILL ENHANCE STORM CHANCES THROUGH THIS PERIOD. WITH VERY WEAK FLOW FORECAST TO EXIST OVER THE CWA...MESOSCALE FEATURES WILL CONTINUE TO DOMINATE THE DAILY WEATHER PATTERN. MESOSCALE FEATURES...BY PHYSICAL DEFINITION... CANNOT BE FORECAST MORE THAN ABOUT 12 HOURS OUT AT BEST...SO DID NOT PUT A WHOLE LOT OF DETAIL IN PRECIPITATION CHANCES THROUGH THIS PERIOD AS A RESULT. FOR PLANNING PURPOSES...JUST KEEP IN MIND THAT THE LARGE SCALE PATTERN IS SUPPORTIVE OF SCATTERED SHOWERS AND STORMS EACH DAY. THE FORECAST WILL CHANGE DEPENDING ON THE MESOSCALE FEATURES AS THEY ARE RESOLVED...INCREASING RAIN CHANCES FOR SOME AREAS WHILE LOWERING THEM FOR OTHERS. JUST LOOKING AT THE PATTERN...LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING WILL BE THE PRIMARY HAZARDS. LOCALLY STRONG WIND GUSTS CAN NOT BE RULED OUT FOR ANY STORMS THAT OCCUR DURING THE PEAK HEATING HOURS OF THE DAY. FRIDAY THROUGH SUNDAY...WENT AHEAD AND TOOK RAIN CHANCES OUT FOR MOST LOCATIONS DURING THIS PERIOD. THE 00Z ECMWF STOPPED ADVERTISING THAT STALLED OUT UPPER LOW OVER NEW MEXICO THAT IT HAD BEEN SHOWING FOR THE PAST 24 HOURS. IT NOW SHOWS WEAK RIDGING ALOFT OVER THE CWA FOR NEXT WEEKEND WITH IS MORE IN LINE WITH WHAT THE GFS HAS BEEN SHOWING FOR DAYS. THINGS COULD CHANGE OF COURSE AS THE RELEVANT FEATURES REMAIN WELL OUT OVER THE OPEN WATERS OF THE PACIFIC. AT THIS TIME...SINCE MOST GUIDANCE AS ADVERTISING RIDGING ALOFT...DECIDED TO OPT WITH A DRY FORECAST AND ABOVE NORMAL TEMPERATURES. CAVANAUGH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 84 75 90 75 88 / 30 40 40 30 40 WACO, TX 86 73 89 73 87 / 100 20 40 30 50 PARIS, TX 84 71 85 71 85 / 30 50 40 30 40 DENTON, TX 83 72 89 72 87 / 30 50 40 30 40 MCKINNEY, TX 83 73 89 73 87 / 30 50 40 30 40 DALLAS, TX 85 75 89 75 87 / 30 40 40 30 40 TERRELL, TX 84 76 91 73 88 / 30 30 40 30 40 CORSICANA, TX 87 74 88 73 86 / 30 30 40 30 50 TEMPLE, TX 87 73 89 73 87 / 100 20 40 30 50 MINERAL WELLS, TX 84 71 88 71 87 / 40 50 40 30 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 58/82
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1141 AM CDT MON JUN 23 2014 .UPDATE... INCREASED POPS TODAY. && .DISCUSSION... CONVECTION HOLDING TOGETHER AND EXPANDING IN COVERAGE. HAVE RAISED POPS TO LIKELY OVER THE NW TWO-THIRDS OF THE AREA. RAP 13 PERFORMING WELL AND HAVE LEANED TOWARD IT`S SOLUTION FOR THE REMAINDER OF THE DAY. OF INTEREST...THE RAP BRINGS A STRONG S/WV OVER THE CENTRAL PLAINS INTO NORTH TEXAS THIS EVENING AND BRINGS ANOTHER ROUND OF SHRA/TSRA INTO THE NORTHERN HALF OF THE CWA. THE NAM 12 SUPPORTS THIS SCENARIO AS WELL. 43 && .PREV DISCUSSION... /ISSUED 930 AM CDT MON JUN 23 2014/ UPDATE... SEE MORNING UPDATE. DISCUSSION... A STRONG OUTFLOW BOUNDARY IS HEADING SOUTH AND CONVECTION IS GETTING CLOSE TO THE NORTHERN PART OF THE CWA. SHORT TERM GUIDANCE STILL SUGGESTS WEAKENING OF THIS SYSTEM BUT THE RAP 13 AND TEXAS TECH 3 KM BECOMING MORE BULLISH WITH POPS OVER THE NW THIRD OF THE CWA. RAISED POPS TO CHANCE OVER THE NW ZONES. 12Z CRP SOUNDING HAS A PW VALUE OF 2.06 INCHES WITH SOME DRY AIR AT 700 MB. THE CONVECTIVE TEMPS ARE IN THE MID 80S WHICH IS MORE THAN REACHABLE. SHORT TERM GUIDANCE SUGGESTS CONVECTION WILL WANE THIS AFTN AS SOME OF THE DRIER AIR ALOFT MIXES TO THE SURFACE. WILL RE-EVALUATE THAT TREND AFTER 17Z. 43 PREV DISCUSSION... /ISSUED 648 AM CDT MON JUN 23 2014/ DISCUSSION... UPDATED AVIATION SECTION. AVIATION... LATEST RADAR COMPOSITES SHOW BAND OF STORMS SITUATED OVER NORTH TEXAS...NEAR THE DFW METROPLEX. LINE OF STORMS WAS MOVING SOUTHEAST AROUND 45 MPH. INFRARED SATELLITE SHOWING WARMING CLOUD TOPS AND OVERALL WEAKENING OF THIS CONVECTIVE COMPLEX. AVAILABLE MESO MODELS ARE NOT HANDLING THIS SYSTEM VERY WELL...BUT THESE ALSO SHOW A DISSIPATION OF THE LINE GOING FORWARD. TAFS ARE WRITTEN WITH THE IDEA THAT THIS DISSIPATING TREND WILL CONTINUE...BUT NOT COMPLETELY CERTAIN IT WILL OCCUR GIVEN FAIRLY UNSTABLE AIRMASS DOWNSTREAM. FOR THIS REASON HAVE GONE WITH A VCTS FOR CLL...UTS AND CXO BASED ON TIMING OF CURRENT LINE BUT BASED ON LOW PROBABILITY IT WILL SURVIVE AS A LINE. FARTHER SOUTH AND EAST...EVEN LESS LIKELY LINE WILL MAKE IT...AND WILL CONTINUE WITH NO MENTION OF PRECIP THERE IN THE TAFS. OTHERWISE EXPECT A DECREASE IN CONVECTION TONIGHT...WITH JUST SOME PATCHY MVFR LATE TONIGHT FOR IAH ON NORTH AND NORTHWEST. PREV DISCUSSION... /ISSUED 415 AM CDT MON JUN 23 2014/ DISCUSSION... REGIONAL SATELLITE IMAGERY AND RADAR SHOW MATURE SQUALL LINE PUSHING THROUGH OK/TX AND RED RIVER REGION. CLOSER TO HOUSTON MAINLY OBSERVING SPOTTY SHOWERS BUT NOT MUCH PRECIP HITTING THE GROUND. SQUALL LINE SHOULD CONTINUE TO PUSH SOUTH TOWARDS THE AREA THIS MORNING WITH STRONG COLD POOL BEHIND IT. RAPID REFRESH AND WRF RUNS SHOW THE SQUALL LINE BREAKING UP BEFORE REACHING COLLEGE STATION. KEPT THE FORECAST IN LINE WITH THIS THINKING FOR THE MORNING BUT CONCERNED LINE COULD PUSH FARTHER SOUTH THAN EXPECTED SINCE THERE IS LITTLE SUBSIDENCE AND DRY AIR TO IMPEDE ITS PROGRESS. FORECAST HOLDS WITH 20 POPS AS STILL POSSIBLE FOR ISO CONVECTION TO DEVELOP DURING THE HEAT OF THE DAY. WATER VAPOR IMAGERY AND 00Z 500MB ANALYSIS SHOW TROUGHING OVER MUCH OF TX. UPPER RIDGE IS NOT ALL THAT STRONG AND LIKELY SPLIT BETWEEN NORTHERN MEXICO AND THE C GULF. GLOBAL MODELS ALL SUPPORT TROUGHING OVER TX THROUGH THE END OF THE WEEK. MODELS ALSO SHOW A SURGE IN TROPICAL MOISTURE LATE TUE INTO WED. GIVEN PERCIP WATER VALUES OF NEAR 2 INCHES ACROSS MUCH OF THE AREA FOR WED/THUR DECIDED TO GO WITH 50/60 POPS EACH OF THOSE DAYS. TROPICAL MOISTURE WILL BE SUPPORTIVE OF 1-2 INCH AN HOUR RAINRATES IN STRONGER STORMS SO LOCALLY HEAVY RAINFALL A CONCERN. THIS COULD RESULT IN URBAN FLOODING AND RAPID INCREASES IN BAYOUS. AREAWIDE RAINFALL TOTALS OF 1 TO 2 INCHES OF RAIN WILL BE POSSIBLE FOR THE LATER HALF OF THE WEEK. THE TRICK TO THE FORECAST WILL BE WHERE THE ISOLATED 3 TO 5 INCH RAINFALL AMOUNTS SET UP WHICH COULD LEAD TO FLOODING IMPACTS. UPPER LEVEL RIDGING DOES TRY TO STRENGTHEN DEPENDING ON THE MODEL. THE ECMWF SEEMS TO BE MORE ROBUST WITH THE RIDGE SUNDAY INTO NEXT MONDAY. MEANWHILE THE GFS MAINTAINS A SHEAR AXIS OVER THE NW GULF. RIGHT NOW WILL STILL CARRY SOME LOWER POPS. THINK FRI/SAT WILL BE DRIER BUT 40 POPS STILL DECENT CHANCES. WILL ALSO KEEP 20 POPS IN THE FORECAST FOR SUN/MON AS THERE STILL SHOULD BE PLENTY OF DEEP MOISTURE IN PLACE AND RIDGING STRENGTH WILL STILL BE RELATIVELY UNKNOWN. TEMPERATURES SHOULD REMAIN NEAR NORMAL FOR THE COMING WEEK MAYBE A DEGREE OR TWO COOLER WITH THUNDERSTORM CHANCES. THIS MEANS UPPER 80S TO LOW 90S WITH MIN TEMPS IN THE MID 70S. STILL COULD GET SOME RAIN COOLED LOW 70S OR UPPER 60S BUT DIFFICULT TO FORECAST THOSE OCCURRENCES SINCE IT WILL DEPEND ON THE CONVECTION. THE NICE THING ABOUT THIS FORECAST IS THAT TEMPS SHOULD REMAIN BELOW 95F THROUGH ALMOST THE END OF JUNE. CLIMATE FACTOID...CLL/IAH/HOU HAVE YET TO REACH 95F OR HIGHER THIS YEAR FOR A MAX TEMP. 39 MARINE... LIGHT TO MODERATE ONSHORE FLOW WILL CONTINUE THE NEXT FEW DAYS WITH SUSTAINED 10 METER WINDS GENERALLY ONSHORE AROUND 10 TO 15 KNOTS THROUGH TUESDAY. GRADIENT IS FORECAST TO TIGHTEN SOMEWHAT MID TO LATE WEEK WITH SMALL CRAFT EXERCISE CAUTION WINDS A POSSIBILITY BY WED OR THU. WITH PERSISTENT SE FLOW AND LONG FETCH SEAS ARE EXPECTED TO GRADUALLY BUILD THROUGH THE WEEK...WITH 6 TO 9 FOOT SEAS A GOOD BET BY THURSDAY AND FRIDAY. 46 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 93 74 90 74 88 / 60 30 40 20 60 HOUSTON (IAH) 92 76 90 75 88 / 60 20 40 20 60 GALVESTON (GLS) 89 80 88 80 87 / 20 20 30 40 50 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...43
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1124 AM CDT MON JUN 23 2014 .UPDATE... THIS MORNINGS MCS CONTINUES TO WEAKEN OVER THE SOUTHERN COUNTIES OF THE CWA. THE MOVEMENT OF THE REMAINING SHOWERS AND STORMS IS TO THE EAST AND SOUTHEAST. AN OUTFLOW BOUNDARY CAN BE SEEN ON THE KGRK RADAR PUSHING AHEAD OF THE LEADING EDGE INTO THE HILL COUNTRY AND SOUTHEAST TEXAS. THIS OUTFLOW BOUNDARY WILL LIKELY NOT BE A FACTOR FOR AFTERNOON CONVECTION IN OUR CWA WITH THE BOUNDARY LOCATED SOUTH OF THE REGION AND THE MEAN STEERING FLOW TO THE SOUTHEAST. HOWEVER...ANOTHER BOUNDARY/FRONT CAN BE SEEN ON THE KFWS RADAR AND SURFACE OBS ACROSS OKLAHOMA AND NORTHWEST TEXAS... MOVING INTO THE NORTHWESTERN PORTIONS OF THE CWA. THE WINDS AT BOWIE HAVE COME AROUND TO THE NORTH AND OTHER SITES ALONG THE RED RIVER HAVE SHIFTED TO THE WEST. BOTH THE HRRR AND RAP ARE DEVELOPING CONVECTION ALONG THIS BOUNDARY EARLY THIS AFTERNOON WITH THE FOCUS FOR CONVECTION SLOWLY MOVING SOUTH THROUGH THE AFTERNOON HOURS. DESPITE THE PRESENCE OF THE BOUNDARY IN OUR NORTHWESTERN COUNTIES...THE AFTERNOON FORECAST IS STILL MUDDLED BY THIS MORNING/S MCS. SURFACE TEMPERATURES ACROSS MOST OF THE REGION ARE COOL IN THE UPPER 60S AND LOWER 70S. ANALYSIS OF AMDAR SOUNDINGS SHOW THE TEMPERATURES JUST ABOVE THE SURFACE HAVE RAPIDLY WARMED IN THE WAKE OF THE MCS DUE TO SUBSIDENCE ON THE BACK SIDE. A RECENT AMDAR SOUNDING FROM DFW AT 1555Z SHOWS TEMPERATURES AT 900 MB HAVE WARMED 9 DEGREES CELSIUS SINCE THE RAIN STARTED. IN ADDITION...THE LOWER LEVELS OF THE ATMOSPHERE HAVE SIGNFICANTLY DRIED UP TO ABOUT 600 MB. IN ORDER TO BREAK THE CAP THAT HAS DEVELOPED IN THE WAKE OF THE MCS...SURFACE TEMPERATURES WOULD HAVE TO WARM INTO THE MID AND UPPER 90S AND THAT IS NOT GOING TO HAPPEN TODAY. WHAT WE WILL LIKELY SEE IS ISOLATED TO SCATTERED ELEVATED CONVECTION DEVELOP WITH HELP FROM A SHORTWAVE MOVING NORTHWEST TO SOUTHEAST ACROSS PRIMARILY THE NORTHERN HALF OF THE REGION THIS AFTERNOON. IF THE ELEVATED CONVECTION IS ABLE TO SATURATE THE LOWER LEVELS OF THE ATMOSPHERE OVER TIME /AND THUS EFFECTIVELY COOL THE TEMPERATURES AROUND 900-800 MB/...IT IS POSSIBLE WE COULD HAVE SURFACE BASED CONVECTION LATER THIS AFTERNOON...IN PARTICULAR AROUND ANY BOUNDARIES OR THE FRONT. HOWEVER...CONFIDENCE IN SURFACE BASED CONVECTION IS RELATIVELY LOW FOR THE REMAINDER OF THE DAY. IN ANTICIPATION OF ELEVATED CONVECTION FOR THE REMAINDER OF THE DAY...TAILORED POPS TO 30 PERCENT IN THE EAST AND 40 PERCENT IN THE WEST. THE MODELS ARE INDICATING MUCH OF THE CONVECTION MAY OCCUR WEST OF INTERSTATE 35 WHERE THE CLOUDS ARE ALREADY THINNING OUT...SURFACE TEMPERATURES WILL BE THE WARMEST AND INSTABILITY WILL THUS BE THE HIGHEST IN THE AREA. WITH ANY STORMS TODAY...GUSTY WINDS...LIGHTNING...AND HEAVY RAINFALL WILL BE THE MAIN THREATS. STORM MOTION TODAY IS EXPECTED TO BE FASTER THAN THE LAST FEW DAYS WHICH SHOULD HELP MITIGATE ANY FLASH FLOOD THREAT THIS AFTERNOON BUT WITH A CONTINUED THREAT FOR HEAVY RAIN...WILL NEED TO CLOSELY MONITOR RADAR TRENDS. 82/JLD && .AVIATION... /ISSUED 616 AM CDT MON JUN 23 2014/ SQUALL LINE IS CURRENTLY MOVING OVER THE METROPLEX TERMINAL LOCATIONS...AND WIND GUSTS OF 35 KT TO 50 KT WILL BE POSSIBLE THROUGH 13Z. THUNDERSTORMS WILL REACH WACO BY 15Z BUT SHOULD BE IN A WEAKENED STATE BY THEN. NORTHWEST WINDS WITH THE OUTFLOW BOUNDARY WILL SHIFT BACK AROUND TO THE SOUTH LATER THIS MORNING. ADDITIONAL CONVECTION IS POSSIBLE AGAIN TONIGHT...BUT WE WILL GET A GOOD LOOK AT FUTURE MODEL DATA BEFORE PINPOINTING SPECIFIC TIMES FOR TS IN AREA FORECASTS. 30 && .PREV DISCUSSION... /ISSUED 414 AM CDT MON JUN 23 2014/ THE PRIMARY WEATHER FEATURE OF INTEREST EARLY THIS MORNING WAS A SQUALL LINE LOCATED FROM NORMAN TO WICHITA FALLS TO LUBBOCK AS OF 4 AM CDT. THIS SQUALL LINE WAS A BIT WEAKER THAN IT WAS AROUND MIDNIGHT...HOWEVER ITS RADAR REFLECTIVITY STRUCTURE CONTINUED TO SHOW A WELL ORGANIZED LINEAR MCS WITH FAIRLY UPRIGHT UPDRAFTS AND STRONG CONVECTION ALONG THE LEADING EDGE OF ITS OUTFLOW BOUNDARY. THIS STRUCTURE LIKELY MEANS THAT THIS SQUALL LINE WILL NOT FALL APART OR SLOW DOWN MUCH AS IT CONTINUES SOUTHEAST OVER NORTH TEXAS EARLY THIS MORNING. THE PORTION OF THE SQUALL LINE THAT WILL LIKELY REACH OUR NORTHWESTERN CWA FIRST WAS STILL SEVERE WARNED BY WFO OUN AT THE TIME OF THIS DISCUSSION. KFDR RADAR OBSERVED A 50-54 KT INBOUND VELOCITY AT AROUND 100 FT AGL WITHIN THIS WARNING. THE SQUALL LINE MAY CONTINUE TO WEAKEN A BIT AS IT MOVES TOWARDS NORTH TEXAS...BUT STRONG TO DAMAGING WIND GUSTS WILL CERTAINLY BE A POSSIBILITY WITHIN THIS LINE THIS MORNING. AT THIS TIME...THE SQUALL LINE WAS ON TRACK TO MOVE THROUGH THE DFW METROPLEX FROM APPROXIMATELY 6 AM TO 8 AM. THIS TIMING MAY CHANGE AS INTENSITY CHANGES WITHIN THE LINE OF STORMS...HOWEVER IMPACTS TO THE MORNING RUSH HOUR COMMUTE LOOK LIKELY AT THIS TIME. ASIDE FROM STRONG WIND GUSTS...LOCALLY HEAVY RAINFALL IS EXPECTED TO BE A PROBLEM AS WELL. LOCALIZED FLOODING IS CONTINGENT UPON THE SPEED OF THE STORMS AND THE SQUALL LINE IN GENERAL THIS MORNING. THE TEXAS TECH WRF INDICATES THAT THE SQUALL LINE...OR ITS REMNANTS...WILL PUSH THROUGH THE ENTIRE CWA FROM 12 TO 18Z. IF THIS SCENARIO PANS OUT...LOCALIZED FLOODING IS LESS LIKELY BECAUSE STORMS WILL BE MOVING THROUGH THE AREA TOO QUICKLY. MANY OTHER HIGH-RESOLUTION GUIDANCE MEMBERS WEAKEN THE SQUALL LINE TO THE POINT THAT IT DROPS A NEARLY STATIONARY BOUNDARY NEAR OR JUST SOUTH OF INTERSTATE 20 BY LATE THIS MORNING. IF THIS OCCURS...IT`S ONLY GOING TO HAPPEN BECAUSE THE SQUALL LINE SLOWS DOWN CONSIDERABLY FROM ITS CURRENT PACE. ANY ONGOING RAIN SHOWER AND THUNDERSTORM ACTIVITY IN THIS SCENARIO WOULD BE MORE LIKELY TO PRODUCE LOCALIZED FLOODING AS STORMS WILL SIMPLY BE MOVING SLOWER. EITHER WAY...LOCALLY HEAVY RAIN WILL OCCUR WITH ANY THUNDERSTORM ACTIVITY ALONG THE SQUALL LINE BECAUSE MODELS INDICATE THAT PWATS ONLY INCREASE OUT AHEAD OF THE SQUALL LINE ACROSS NORTH TEXAS THIS MORNING. WITH LITTLE AIRCRAFT ACTIVITY (FOR AMDAR SOUNDINGS) OVERNIGHT...ITS DIFFICULT TO ESTABLISH IF THIS IS REALISTIC OR NOT. HOWEVER LOOKING AT THE GOES SOUNDER OUTPUT...THERE IS A PLUME OF 2 INCH (OBSERVED AS 50 MM) PWATS LOCATED JUST SOUTH OF THE DFW AREA...CONTINUING SOUTH OVER CENTRAL TEXAS. HOW FAR NORTH OR EAST THIS PLUME EXTENDS IS UNKNOWN BECAUSE THE SATELLITE CAN NOT SEE THROUGH THICK UPPER LEVEL CLOUDS OVER THESE AREAS. THE FACT THAT 2 INCH PWATS ARE OBSERVED TO THE SOUTHWEST OF WHERE MODELS DEPICT 2 INCH PWATS THIS MORNING (GENERALLY NORTH OF I-20 AND EAST OF I-35) IS A GOOD SIGN THAT THE MODELS PROBABLY HAVE THIS RIGHT. AS A RESULT...WENT AHEAD WITH A MENTION OF HEAVY RAINFALL IN THE WORDED FORECAST THIS MORNING...HIGHLIGHTING AREAS NORTH OF INTERSTATE 20 AS HAVING THE HIGHEST CHANCE AT SEEING LOCALLY HEAVY RAINS. IN REALITY...WE WILL JUST HAVE TO WATCH AND SEE HOW THE SQUALL LINE EVOLVES BECAUSE WHERE EVER THE STRONGEST THUNDERSTORM ACTIVITY GOES...THE HEAVY RAIN WILL FOLLOW SUIT. THE IMPACTS WERE NOT EXPECTED TO BE WIDESPREAD ENOUGH TO RESULT IN LARGE SCALE FLOODING...SO NO FLOOD WATCH WILL BE ISSUED WITH THIS FORECAST PACKAGE. WILL MONITOR STORMS AND HANDLE LOCALIZED FLOODING TACTICALLY VIA WARNINGS...GRAPHICS AND SOCIAL MEDIA DISSEMINATION. FOR THIS AFTERNOON...NEW THUNDERSTORM CHANCES REALLY DEPEND ON WHAT HAPPENS WITH OUR SQUALL LINE THIS MORNING. MANY MODELS SHOW A GOOD QPF SIGNAL IN LINE WITH THE SQUALL LINE...BUT MOST UNFORTUNATELY FAIL TO CARRY THE DYNAMICS OF THE SQUALL LINE INTO THE MODEL MASS FIELDS. FOR INSTANCE...NOT ONE OPERATIONAL MODEL BOTHERS TO BRING A WIND SHIFT LINE INTO THE CWA WITH THE SQUALL LINE QPF BLOB THIS MORNING. THESE MODELS ALSO FAIL TO SUFFICIENTLY STABILIZE/COOL THE LOWER TROPOSPHERE BEHIND THE SQUALL LINE. THIS PRESENTS A BIG FORECAST PROBLEM AS BOTH OF THESE FACTORS WILL PLAY A HUGE ROLE IN THUNDERSTORM CHANCES FOR THIS AFTERNOON. THE TEXAS TECH WRF AND THE 4 KM NAM BOTH AT LEAST INDICATED SOME RESPONSE IN THE LOW-LEVEL WIND FIELD...SO THESE MODELS WERE WEIGHED MORE HEAVILY FOR THIS AFTERNOON`S THUNDERSTORM FORECAST. AN 08Z OBJECTIVE SURFACE ANALYSIS INDICATED A THETA-E DROP OF AROUND 11 KELVIN BEHIND THE SQUALL LINE THIS MORNING. AS FAR AS COLD POOLS GO BEHIND SQUALL LINES...THIS IS NOT SUPER IMPRESSIVE...BUT WILL NOT SIMPLY DISSIPATE WITH A FEW HOURS OF DAYTIME HEATING EITHER. AS A RESULT...WHEREVER THE SQUALL LINE LEAVES AN OUTFLOW BOUNDARY THIS MORNING...IT IS LIKELY TO HANG AROUND AND MAINTAIN SOME IDENTITY FOR THIS AFTERNOON. AT THIS TIME...USING THE TEXAS TECH WRF`S SURFACE WIND FIELD AS A PROXY FOR THE OUTFLOW BOUNDARY`S LOCATION THIS AFTERNOON...THINK IT WILL END UP SOUTH OF INTERSTATE 20. AS A RESULT...WENT AHEAD AND LOWERED POPS FOR LOCATIONS NORTH OF THE INTERSTATE FOR THIS AFTERNOON FROM THE PREVIOUS FORECAST. IF THE SQUALL LINE ACTUALLY MOVES ALL THE WAY THROUGH CENTRAL TEXAS BY 18Z AS THE TEXAS TECH WRF REFLECTIVITY SUGGESTS...IT MAY COMPLETELY SHUT DOWN THUNDERSTORM CHANCES FOR THE CWA FOR THIS AFTERNOON. AS IT STANDS...HAVE 30 TO 40 POPS IN THE FORECAST SOUTH OF INTERSTATE 20 AND WEST OF INTERSTATE 35 FOR THIS AFTERNOON REPRESENTING THE MAXIMUM POPS ACROSS THE CWA. HIGHLIGHTED AREAS WEST OF INTERSTATE 35 BECAUSE MOST MODELS INDICATE THAT A WEAK SHORTWAVE TROUGH CURRENTLY LOCATED ALONG THE ARIZONA/MEXICO BORDER WILL MOVE EAST AND PROVIDE SOME FORCING FOR ASCENT OVER WEST- CENTRAL TEXAS BY 00Z TODAY. IF THERE REALLY IS AN OUTFLOW BOUNDARY STALLED OUT IN PLACE HERE...THE WEAK FORCING FOR ASCENT FROM THIS TROUGH COMBINED WITH THE BOUNDARY SHOULD BE AN IDEAL PLACE FOR NEW THUNDERSTORMS TO DEVELOP BY LATE THIS AFTERNOON. AS MENTIONED ABOVE...IF THE OUTFLOW BOUNDARY IS ELSEWHERE BY THIS AFTERNOON...POPS WILL NEED TO BE ADJUSTED ACCORDINGLY. THE 4 KM NAM INDICATES THAT THIS BOUNDARY IS VERY IMPORTANT FOR THIS AFTERNOON STORMS AS IT BLOWS UP SEVERAL CLUSTERS OF VERY STRONG LOOKING CONVECTION ALONG THIS BOUNDARY BY 00Z. THE NSSL WRF ON THE OTHER HAND INDICATES THAT THE OUTFLOW BOUNDARY WILL NOT BE AS IMPORTANT AS AN MCV WITH REGARDS TO AFTERNOON THUNDERSTORM CHANCES. THIS MODEL KEEPS WELL DEFINED MCV IN PLACE OVER EAST CENTRAL OKLAHOMA THIS AFTERNOON AND CONCENTRATES THUNDERSTORM ACTIVITY THERE INSTEAD OF ALONG THE OUTFLOW BOUNDARY OVER NORTH/CENTRAL TEXAS. IT IS DIFFICULT TO KNOW WHAT WILL BE IMPORTANT UNTIL THIS MORNINGS SQUALL LINE DISSIPATES AND WE CAN REEVALUATE WHAT THE THERMODYNAMIC AND KINEMATIC ENVIRONMENT LOOKS LIKE AT THAT TIME. FOR TONIGHT...MOST MODELS INDICATE THAT OUR OUTFLOW BOUNDARY WILL LIFT NORTH TO THE RED RIVER AND BECOME THE FOCUS FOR NEW THUNDERSTORM ACTIVITY OVERNIGHT. WENT AHEAD AND KEPT HIGHER POPS OVER THE NORTHERN CWA FOR TONIGHT AS A RESULT. IF THE OUTFLOW BOUNDARY MAINTAINS ANY IDENTITY THROUGHOUT THE AFTERNOON HOURS OF THE DAY...IT WILL PROBABLY SERVE TO ENHANCE THE SLOPE OF LOW- LEVEL ISENTROPIC SURFACES PERPENDICULAR TO LOW-LEVEL WINDS RESULTING IN ENHANCED LIFT. THE NORTHERN CWA SHOULD BENEFIT FROM THIS ENHANCED LOW-LEVEL LIFT MORE SO THAN THE SOUTH. TUESDAY THROUGH THURSDAY...MORE MODELS ARE SHOWING THAT A COL IN THE UPPER LEVEL FLOW FIELD WILL SET UP OVER NORTH TEXAS DURING THIS TIME FRAME. AS A RESULT...KEPT BROAD BRUSHED POPS IN PLACE FOR ALL AREAS. HAVE SLIGHTLY HIGHER POPS ADVERTISED DURING THE AFTERNOON HOURS OF THE DAY EACH DAY AS ANY HEATING COMBINED WITH ANY WEAK UPPER TROUGH ALOFT WILL ENHANCE STORM CHANCES THROUGH THIS PERIOD. WITH VERY WEAK FLOW FORECAST TO EXIST OVER THE CWA...MESOSCALE FEATURES WILL CONTINUE TO DOMINATE THE DAILY WEATHER PATTERN. MESOSCALE FEATURES...BY PHYSICAL DEFINITION... CANNOT BE FORECAST MORE THAN ABOUT 12 HOURS OUT AT BEST...SO DID NOT PUT A WHOLE LOT OF DETAIL IN PRECIPITATION CHANCES THROUGH THIS PERIOD AS A RESULT. FOR PLANNING PURPOSES...JUST KEEP IN MIND THAT THE LARGE SCALE PATTERN IS SUPPORTIVE OF SCATTERED SHOWERS AND STORMS EACH DAY. THE FORECAST WILL CHANGE DEPENDING ON THE MESOSCALE FEATURES AS THEY ARE RESOLVED...INCREASING RAIN CHANCES FOR SOME AREAS WHILE LOWERING THEM FOR OTHERS. JUST LOOKING AT THE PATTERN...LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING WILL BE THE PRIMARY HAZARDS. LOCALLY STRONG WIND GUSTS CAN NOT BE RULED OUT FOR ANY STORMS THAT OCCUR DURING THE PEAK HEATING HOURS OF THE DAY. FRIDAY THROUGH SUNDAY...WENT AHEAD AND TOOK RAIN CHANCES OUT FOR MOST LOCATIONS DURING THIS PERIOD. THE 00Z ECMWF STOPPED ADVERTISING THAT STALLED OUT UPPER LOW OVER NEW MEXICO THAT IT HAD BEEN SHOWING FOR THE PAST 24 HOURS. IT NOW SHOWS WEAK RIDGING ALOFT OVER THE CWA FOR NEXT WEEKEND WITH IS MORE IN LINE WITH WHAT THE GFS HAS BEEN SHOWING FOR DAYS. THINGS COULD CHANGE OF COURSE AS THE RELEVANT FEATURES REMAIN WELL OUT OVER THE OPEN WATERS OF THE PACIFIC. AT THIS TIME...SINCE MOST GUIDANCE AS ADVERTISING RIDGING ALOFT...DECIDED TO OPT WITH A DRY FORECAST AND ABOVE NORMAL TEMPERATURES. CAVANAUGH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 84 75 90 75 88 / 30 40 40 30 40 WACO, TX 86 73 89 73 87 / 100 20 40 30 50 PARIS, TX 84 71 85 71 85 / 30 50 40 30 40 DENTON, TX 83 72 89 72 87 / 30 50 40 30 40 MCKINNEY, TX 83 73 89 73 87 / 30 50 40 30 40 DALLAS, TX 85 75 89 75 87 / 30 40 40 30 40 TERRELL, TX 84 76 91 73 88 / 30 30 40 30 40 CORSICANA, TX 87 74 88 73 86 / 30 30 40 30 50 TEMPLE, TX 87 73 89 73 87 / 100 20 40 30 50 MINERAL WELLS, TX 84 71 88 71 87 / 40 50 40 30 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 58/82
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
313 PM CDT MON JUN 23 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 313 PM CDT MON JUN 23 2014 THE MAIN FOCUS INTO TOMORROW IS WITH HOW LONG THE ISOLATED CONVECTION WILL HOLD ON FOR THIS AFTERNOON/EVENING AND THEN WITH THE PRECIPITATION CHANCES TOMORROW. CLOUD COVER HAS BEEN SLOW TO ERODE TODAY AS A COLD FRONT APPROACHES FROM THE WEST AND A MID LEVEL TROUGH PROPAGATES NORTHEAST FROM IOWA INTO THE WESTERN GREAT LAKES. SOME ISOLATED CONVECTION HAS INITIATED ALONG A COLD FRONT IN SOUTHEAST MINNESOTA WHERE MLCAPE IS AROUND 500-1000 J/KG. THE COMBINATION OF THE APPROACHING MID LEVEL SHORT WAVE TROUGH AND THE SLOW MOVING SURFACE BOUNDARY HAS LEAD TO SOME FUNNEL CLOUDS FORMING CLOSER TO THE TWIN CITIES. THIS DEVELOPMENT WILL REMAIN POSSIBLE FOR A FEW HOURS HERE BEFORE THE SUN STARTS TO SET AND SB/MLCAPE STARTS TO DROP OFF. THE PAST FEW RUNS OF THE HRRR HAVE DEVELOPED SOME SMALL COLD POOLS WITH THIS CONVECTION AND TRIES TO KEEP IT GOING THROUGH THE EARLY EVENING HOURS ACROSS WESTERN WISCONSIN. THINKING THAT THESE SOLUTIONS ARE A BIT OVERDONE AS IT HAS SURFACE TEMPERATURES GETTING INTO THE 90S...BUT WILL KEEP SOME PRECIPITATION CHANCES GOING INTO THE EVENING AHEAD OF THIS FRONT. THE FOCUS THEN GOES INTO TOMORROW AS A MID LEVEL TROUGH CURRENTLY OVER SOUTHERN MANITOBA DROPS DOWN INTO THE REGION. THE STRONGEST 500-300MB PV ADVECTION RUNS FROM SOUTHERN MINNESOTA THROUGH CENTRAL WISCONSIN AS THE SURFACE COLD FRONT DRIFTS DOWN INTO THE REGION. THE THINKING IS THAT THE HIGHEST CHANCES FOR ANY SHOWERS/STORMS SHOULD BE ALONG THIS CORRIDOR. THE 23.12Z GUIDANCE ALL SUGGEST THAT MLCAPE SHOULD REMAIN FAIRLY TAME AT 500-1000 J/KG AHEAD OF THE FRONT WITH LITTLE TO NO DEEP SHEAR TO WORK WITH...SO SUSPECT THAT ANY CONVECTION WILL REMAIN OF THE PULSE NATURE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 313 PM CDT MON JUN 23 2014 WITH THIS COLD FRONT TO THE SOUTH OF THE REGION THROUGH THE REST OF THE WORK WEEK...TEMPERATURES WILL BE SEASONAL OR JUST BELOW SEASONAL UNTIL IT GETS KICKED BACK TO THE NORTH AS A WARM FRONT BY NEXT WEEKEND. UNTIL THEN...CONFIDENCE IN PRECIPITATION CHANCES IS NOT VERY HIGH AS MUCH OF IT WILL DEPEND ON WHETHER ANY CONVECTIVE SYSTEMS TRACK ALONG THE BOUNDARY TO THE SOUTH AND WE SEE THE NORTHERN OVERHANG OF IT. THE 23.12Z GFS/ECMWF HAVE ZONAL FLOW OVER THE REGION FOR WEDNESDAY YET HAS SOME CONVECTION DEVELOPING ALONG THE COLD FRONT/TROUGH THAT THEY HAVE ANALYZED ACROSS THE AREA. THE 23.12Z NAM...MEANWHILE...HAS THE REGION MAINLY DRY EXCEPT FOR A PORTION OF THE FRONT IN CENTRAL IOWA WHERE IT BUILDS SURFACE DEW POINTS INTO THE MID 70S AND TAKES MLCAPE UP TOO HIGH. SO...THERE IS NOT A LOT OF CONFIDENCE IN THE PRECIPITATION CHANCES THROUGH THE END OF THE WEEK BUT AT LEAST EXPECT THAT THE RAINS WILL NOT BE ALL DAY DEALS AND JUST SOME PERIODS WHERE THIS CONVECTION IS POSSIBLE. A PATTERN CHANGE TAKES PLACE FOR NEXT WEEKEND AS A DEEPER MID LEVEL TROUGH DEVELOPS ACROSS THE HIGH PLAINS. THIS FEATURE STALLS OUT AND A NUMBER OF SHORT WAVE TROUGHS ROUND THE SOUTHEASTERN PERIPHERY OF IT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. THIS COULD LEAD TO A MORE ACTIVE PERIOD SEVERE WEATHER-WISE WITH STRONG 500MB WINDS OVERHEAD TO GO ALONG WITH AN UNSTABLE AIR MASS. DETAILS WILL FALL OUT THROUGH THE WEEK...BUT THIS APPEARS TO BE THE TIME FRAME TO WATCH FOR POTENTIAL SEVERE WEATHER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1235 PM CDT MON JUN 23 2014 A COLD FRONT EXTENDS FROM RHINELANDER WI /KRHI/ TO AUSTIN MN /KAUM/. MANY OF THE MESO MODELS CONTINUE TO SUGGEST THAT SOME SCATTERED SHOWERS AND STORMS MAY DEVELOP ALONG THIS FRONT DURING THE AFTERNOON. THESE CHANCES WERE TOO LOW AT THIS TIME TO INCLUDE IN THE TAFS. WITH THE LOSS OF DIURNAL HEATING EXPECT SKIES TO BECOME SCATTERED AFTER 23.23Z. && .HYDROLOGY... ISSUED AT 313 PM CDT MON JUN 23 2014 WHILE THERE ARE CHANCES FOR PRECIPITATION THROUGH THIS WEEK...THE CHANCES FOR HEAVY RAINFALL ARE LOW WITH MOST OF THE BETTER MOISTURE TRANSPORT STAYING SOUTH OF THE REGION. HOWEVER...THERE STILL IS A LOT OF WATER COMING DOWN THE RIVERS FROM CENTRAL MINNESOTA WHERE HEAVY RAIN FELL LAST WEEK. EXPECT AREA RIVERS...ESPECIALLY THE MAIN STEMS...TO STAY UP THROUGH THE WEEK. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...BOYNE HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1235 PM CDT MON JUN 23 2014 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 308 AM CDT MON JUN 23 2014 MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES TODAY AND THEN AGAIN FROM TUESDAY INTO WEDNESDAY. SURFACE ANALYSIS THIS MORNING SHOWS A VERY WEAK AND ILL DEFINED PATTERN ACROSS THE UPPER MIDWEST. THERE IS A WEAK BOUNDARY WORKING EAST ACROSS MINNESOTA WHERE THE WINDS SWITCH AROUND TO THE WEST AND DEW POINTS BEGIN TO SLOWLY DECREASE. IT APPEARS THE FLOW ABOVE THE SURFACE IS COMING AROUND TO THE WEST/NORTHWEST AHEAD OF THE SURFACE BOUNDARY WITH 925 MB VWP WINDS FROM KDMX AND KMPX ALREADY AROUND TO THE WEST/NORTHWEST. THE 23.00Z NAM AND GFS ALONG WITH THE 23.06Z RAP ALL TRY TO GENERATE A WEAK SURFACE WAVE OVER MISSOURI AND MOVE IT NORTHEAST THIS MORNING INTO EASTERN WISCONSIN ALONG THE LOW LEVEL WIND SHIFT BOUNDARY DEPICTED BY THE VWP WINDS. THE LOW LEVEL MOISTURE CONVERGENCE MAY INCREASE FOR A SHORT WHILE THIS MORNING ON THE NORTHWEST SIDE OF THIS LOW TO POSSIBLY HELP GENERATE A FEW SHOWERS ACROSS THE EASTERN PART OF THE FORECAST AREA. WILL CARRY SOME LOW RAIN CHANCES ACROSS THE EAST TO COVER THIS POSSIBILITY THROUGH ABOUT THE MIDDLE OF THE AFTERNOON. THE NEXT CHANCE OF RAIN WILL THEN COME TUESDAY AS A SHORT WAVE TROUGH DROPS OUT OF SOUTHERN CANADA INTO THE UPPER MIDWEST. THIS WAVE DOES NOT LOOK TO BE VERY STRONG BUT SHOULD STILL BRING SOME WEAK PV ADVECTION IN THE 500-300 MB LAYER ACROSS NORTHERN MINNESOTA AND WISCONSIN. ONLY WEAK MOISTURE CONVERGENCE ALONG THE FRONT AND WITH BETWEEN 500 AND 1000 J/KG OF ML CAPE...IT SHOULD BE ENOUGH TO GENERATE SOME SCATTERED ACTIVITY WITH THE BULK OF THIS OCCURRING IN THE AFTERNOON. WITH THIS BOUNDARY STILL IN THE AREA TUESDAY NIGHT...SOME OF THIS ACTIVITY COULD PERSIST PAST DARK NORTHEAST OF THE I94 CORRIDOR WITH THE COVERAGE DIMINISHING AS THE CAPE DECREASES. ANOTHER SHORT WAVE TROUGH IS EXPECTED TO APPROACH FROM THE WEST WEDNESDAY. THE WEAK PV ADVECTION FROM THIS WAVE SHOULD ONLY ADVANCE INTO WESTERN MINNESOTA AND IOWA BY LATE IN THE DAY. HOWEVER...THE WARM AIR ADVECTION AHEAD OF THIS WAVE SHOULD ALLOW 1-3 UBAR/S OF ISENTROPIC UP GLIDE ON THE 300K SURFACE TO START SPREADING IN THROUGH THE DAY AND THIS COULD AGAIN BE ENOUGH TO GENERATE SOME SCATTERED ACTIVITY AS THE ML CAPE INCREASES TO 500-1000 J/KG. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 308 AM CDT MON JUN 23 2014 THE LONGER RANGE MODELS REMAIN CONSISTENT IN SHOWING A TEMPORARY CHANGE IN THE UPPER AIR FLOW AS A LONG WAVE TROUGH DIGS IN OVER THE INTERMOUNTAIN WEST EARLY IN THIS PERIOD. HOWEVER...THE LATEST TRENDS ARE FOR THIS TROUGH TO NOT BE A FAR SOUTH AS THEY NOW INDICATE AN UPPER LEVEL LOW FORMING OVER CENTRAL CANADA OVER THE WEEKEND. THIS ALLOWS A SOUTHWEST FLOW ALOFT TO REMAIN OVER THE UPPER MIDWEST TO CLOSE OUT THE WEEK AND THEN THE LONG WAVE TROUGH SWINGS THROUGH WITH A POSITIVE TILT TO IT. AT THE SURFACE...HIGH PRESSURE SHOULD BE SOUTH OF HUDSONS BAY TO HELP FUNNEL MOISTURE BACK INTO THE UPPER MIDWEST. THE COMBINATION OF THIS MOISTURE FEED AND SHORT WAVE TROUGHS IN THE SOUTHWEST FLOW AND THEN THE LONG WAVE TROUGH ITSELF WILL KEEP THE RAIN CHANCES GOING THROUGH THE PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1235 PM CDT MON JUN 23 2014 A COLD FRONT EXTENDS FROM RHINELAND WI /KRHI/ TO AUSTIN MN /KAUM/. MANY OF THE MESO MODELS CONTINUE TO SUGGEST THAT SOME SCATTERED SHOWERS AND STORMS MAY DEVELOP ALONG THIS FRONT DURING THE AFTERNOON. THESE CHANCES WERE TOO LOW AT THIS TIME TO INCLUDE IN THE TAFS. WITH THE LOSS OF DIURNAL HEATING EXPECT SKIES TO BECOME SCATTERED AFTER 23.23Z. && .HYDROLOGY... ISSUED AT 308 AM CDT MON JUN 23 2014 RIVER FLOOD WARNINGS HAVE BEEN PAIRED BACK TO ALMOST JUST THE MISSISSIPPI RIVER. GIVEN THAT ADDITIONAL HEAVY RAIN DID NOT FALL AND IS NOT EXPECTED OVER THE NEXT SEVERAL DAYS...THE FLOODING WILL BECOME CONFINED TO JUST THE MISSISSIPPI. MANY LOCATIONS ALONG THE MISSISSIPPI ARE EXPECTED TO BE NEAR OR ABOVE FLOOD STAGE THROUGH THE WEEK. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...BOYNE HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
247 PM MDT MON JUN 23 2014 .SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY) ISSUED AT 245 PM MDT MON JUN 23 2014 DEEPER CUMULUS HAVE STARTED TO DEVELOP OVER THE PAST HOUR IN THE CONVERGENCE ALONG THE SOUTHERN LARAMIE RANGE...BUT SO FAR NOT A WHOLE LOT OF UPSCALE GROWTH AS THESE CELLS HAVE MOVED INTO THE PLAINS. DEW POINTS ARE CURRENTLY IN THE UPPER 40S TO MID 50S TO THE EAST OF THE LARAMIE RANGE. THE MODELS CONTINUE TO INDICATE AN ENVIRONMENT CONDUCIVE FOR SOME STRONG TO SEVERE STORMS IN AREAS NEAR THE COLORADO BORDER THROUGH THIS EVENING. SPC MESOANALYSIS SHOWS MLCAPES OF 1000-1250 J/KG STRETCHING ALONG INTERSTATE 80 OVER THE PLAINS COMBINED WITH 35-40 KT OF BULK SHEAR. THE HRRR MODEL HAS A LONE STORM MOVING EASTWARD ALONG THE COLORADO BORDER THROUGH THE LATE AFTN. SO VERY SIMILAR TO YESTERDAY...WE CONTINUE TO EXPECT A MARGINAL SEVERE THREAT OVER LARAMIE COUNTY AND EXTENDING EASTWARD INTO THE SOUTHERN PANHANDLE. KEPT A SLIGHT CHANCE OF TSTMS GOING THROUGH THE NIGHT WITH A WEAK SHORTWAVE MOVING OVERHEAD...WHICH IS CURRENTLY ACROSS SOUTHWESTERN WY. THE REMAINDER OF THE SHORT TERM WILL FEATURE GRADUALLY INCREASING TEMPS AND INSTABILITY. FLOW ALOFT IS STILL WEST TO NORTHWESTERLY ON TUES WITH THE MID LEVEL RIDGE AXIS TO THE WEST OF THE CWA. DEW POINTS INCH UP SLIGHTLY...SO CAPE VALUES WILL INCREASE OVER TODAY WITH THE GFS SHOWING AROUND 1500 J/KG ALONG INTERSTATE 80. INSTABILITY DROPS OFF TO 750 J/KG ACROSS CONVERSE/NIOBRARA COUNTIES AND INTO THE NORTHERN NEBRASKA PANHANDLE. BEST CHANCE OF SEVERE STORMS WILL LIKELY BE OVER AREAS TO THE SOUTH OF A WHEATLAND TO SCOTTSBLUFF LINE. TEMPS ON TUES WILL BE A COUPLE DEGREES WARMER THAN THIS AFTN. THE BEST POTENTIAL FOR MORE WIDESPREAD SEVERE STORMS IS STILL LOOKING LIKE WED. A SFC LOW DEVELOPS OVER NORTH-CENTRAL WY DURING THE AFTN AND WITH PERSISTENT SOUTHEAST WINDS...ADDITIONAL MOISTURE ADVECTION HAS OCCURRED OVER THE PLAINS. DEW POINTS BY WED AFTN ARE INTO THE UPPER 50S AND LOW 60S ALMOST EVERYWHERE TO THE EAST OF THE LARAMIE RANGE WITH CAPE VALUES OF 1500-2000. ALTHOUGH FLOW ALOFT WILL BE WEAKER THAN THE PRECEDING DAYS DUE TO THE PROXIMITY OF THE RIDGE AXIS...THERE IS STILL AROUND 40 KT OF DEEP LAYER SHEAR. ITS A BIT EARLY TO PINPOINT THE AREA OVER THE PLAINS THAN HAS THE BEST POTENTIAL FOR SEVERE STORMS...BUT IT WOULD SEEM TO BE OVER THE NORTHERN HALF...WHICH IS CLOSEST TO A WEAK SHORTWAVE THAN MOVES INTO WESTERN SOUTH DAKOTA DURING THE EVENING. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 225 PM MDT MON JUN 23 2014 MINOR MODEL DIFFERENCES NOTED IN THE MEDIUM RANGE PERIOD. WEAK UPPER RIDGE OVER THE PLAINS YIELDS TO A BROADER UPPER TROUGH BY THE WEEKEND. THE SOUTHWESTERLY FLOW ALOFT VEERS TO WESTERLY. SURFACE PATTERN WILL BE FAIRLY WEAK WITH A RIDGE WEST OF THE MOUNTAINS AND TROUGH ACROSS THE PLAINS. LOW LEVEL CONVERGENCE AND MOISTURE COMBINED WITH PASSING WEAK DISTURBANCES WILL KEEP WIDELY SCATTERED SHOWERS AND TSTORMS IN THE FORECAST THURSDAY THROUGH SATURDAY. SEVERE THREAT WILL BE MINIMAL GIVEN WEAK SHEAR...BUT CANNOT RULE OUT ISOLATED STRONG CONVECTION FOR THE PLAINS. UPPER TROUGH LIFTS NORTHEAST THROUGH THE NORTHERN GREAT PLAINS AND UPPER MIDWEST SUNDAY AND MONDAY WITH DRIER WEST-NORTHWEST FLOW PATTERN. TEMPERATURES WILL AVERAGE ABOVE SEASONAL NORMALS WITH HIGHS IN THE 80S FOR LOWER ELEVATIONS WITH 60S AND 70S FOR THE HIGH COUNTRY. LOWS WILL BE IN THE 40S AND 50S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING) ISSUED AT 1145 AM MDT MON JUN 23 2014 EXPECT ANOTHER ACTIVE AFTERNOON OF TSTORM ACTIVITY...WITH BEST CHANCES ALONG AND EAST OF THE LARAMIE RANGE. VFR CONDITIONS WILL PREVAIL WITH THE EXCEPTION OF MVFR INVOF TSTORMS. THERE IS A SLIGHT RISK FOR GUSTY OUTFLOW WINDS TO 50 KT...HAIL AND HEAVY RAIN FROM CHEYENNE TO SIDNEY. THE CONVECTION WILL LIKELY LINGER THROUGH 03Z IN SOUTHEAST WY AND 06Z FOR THE NEB PANHANDLE. WITH MOIST BOUNDARY LAYER AND LIGHT WINDS...THERE IS THE POTENTIAL FOR MVFR CONDITIONS ACROSS THE PLAINS. && .FIRE WEATHER... ISSUED AT 245 PM MDT MON JUN 23 2014 MINIMAL FIRE WEATHER CONCERNS THROUGH MIDWEEK. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON AND EVENING THROUGH THURSDAY. THE COVERAGE WILL BE HIGHEST AND THE BEST CHANCE OF WETTING RAINS WILL EXIST TO THE EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BEGIN TO INCREASE ON WEDNESDAY AND THURSDAY SUCH THAT MINIMUM AFTERNOON HUMIDITY VALUES WILL DROP TO AROUND 15 PERCENT WEST OF THE LARAMIE RANGE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...FINCH LONG TERM...JAMSKI AVIATION...JAMSKI FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1153 AM MDT MON JUN 23 2014 .UPDATE... ISSUED AT 1112 AM MDT MON JUN 23 2014 MOIST AIRMASS IS IN PLACE ACROSS THE PLAINS THIS MORNING WITH SCATTERED AREAS OF LOW CLOUDS. MODELS SHOW SFC WINDS VEERING TO THE EAST BY THIS AFTN WHICH INCREASES THE BULK SHEAR TO 45-50 KT OFF THE RUC BY THIS AFTN. AFTN INSTABILITY IS SIMILAR TO YESTERDAY WITH THE HIGHEST VALUES (1000-1500 J/KG) IN AREAS ALONG THE COLORADO BORDER. SPC EXTENDED THE SLIGHT RISK NORTHWARD INTO THE SOUTHERN PANHANDLE AND LARAMIE COUNTY WITH THE MORNING UPDATE. COULD VERY WELL BE A REPEAT OF YESTERDAY WITH A FEW MARGINALLY SEVERE STORMS ALONG THE COLORADO BORDER...BUT MORE NUMEROUS ACROSS NORTHEASTERN COLORADO. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 440 AM MDT MON JUN 23 2014 CURRENT IR SATELLITE LOOP SHOWS MOSTLY CLEAR SKIES OVER THE FORECAST AREA WITH SOUTHEAST WYOMING IN BETWEEN UPPER LEVEL SHORT WAVE ACTIVITY EARLY THIS MORNING. THE NEXT SHORTWAVE IS CURRENTLY MOVING SOUTHEAST ACROSS NORTHEAST WYOMING WITH SHOWERS REDEVELOPING ALONG A LINE FROM NEWCASTLE NORTHWARD TOWARDS DEVILS TOWER. MOST MODELS HAVE BEEN TOO AGGRESSIVE WITH THIS SHORTWAVE...SHOWING IT DIGGING SOUTHWARD ACROSS THE AREA TONIGHT...BUT THAT HAS YET TO HAPPEN. THE NAM SEEMS TO BE INITIALIZING THE BEST...SO WILL MAINLY FOLLOW THE 00Z AND 06Z RUNS OVER THE NEXT 24 HOURS. THE NAM SHOWS BANDS OF RAIN SHOWERS DEVELOPING OVER CONVERSE AND NIOBRARA COUNTIES EARLY THIS MORNING AS THE SHORTWAVE DISTURBANCE PUSHES ACROSS EASTERN WYOMING AND INTO THE WESTERN DAKOTAS. THIS SEEMS MORE REALISTIC GIVEN CURRENT OBS ACROSS THE AREA. THE NAM ALSO SHOWS MOST OF THE AFTERNOON SHOWERS AND TSTORMS TODAY FURTHER TO THE SOUTH NEAR THE COLORADO BORDER...BUT THIS IS ALSO CONSISTENT WITH THE OTHER MODELS WHICH SHOW A SIMILAR SOLUTION. LOWERED POP UP NORTH TO AROUND 30 PERCENT AFTER MID TO LATE MORNING...AND INCREASED AREAS ALONG AND JUST NORTH OF THE I80 CORRIDOR IN THE AFTERNOON. EXPECT SIMILAR CONDITIONS TODAY WITH COOLER THAN NORMAL DAYTIME TEMPERATURES BUT ALSO PLENTY OF INSTABILITY...ESPECIALLY WITH THE CLEARING SKIES EARLY THIS MORNING WHICH WILL ALLOW MAXIMUM SURFACE HEATING TODAY. STILL EXPECT A SOMEWHAT HIGHER SEVERE WEATHER THREAT TODAY COMPARED TO YESTERDAY...BUT THERE IS CONCERN OVER CURRENT MODEL SOUNDINGS WHICH SHOW HIGHER LI/S AND LOWER CAPE VALUES LATE IN THE AFTERNOON DUE TO MID TO UPPER LEVEL WARMING. CAPE VALUES STILL AROUND 1500 TO 2500 J/KG EARLY IN THE AFTERNOON BUT QUICKLY LOWER THROUGH MID AFTERNOON...MEANING EITHER CONVECTION WILL START PRETTY EARLY TODAY OR IT WILL BE LIMITED IN COVERAGE THROUGH THIS AFTERNOON. BELIEVE EARLIER CONVECTION INITIATION IS MORE LIKELY GIVEN CURRENT PROFILES...WITH ACTIVITY TRANSITIONING TO RAIN SHOWERS BY LATE IN THE AFTERNOON. THUNDERSTORMS WILL BE MULTI CELLULAR IN NATURE WITH TRAINING ALONG OUTFLOW BOUNDARIES AND SOME PROPAGATION EXPECTED...DUE TO DECENT 40 TO 50 KNOT DEEP LAYER SHEAR. LOCALLY HEAVY RAINFALL AND FLASH FLOODING IS POSSIBLE AS WELL. ON TUESDAY...MODELS NOW SHOW WEST TO NORTHWEST FLOW ALOFT CONTINUING OVER THE AREA WITH A WEAK RIDGE AXIS REMAINING TO THE EAST. YESTERDAY...MODELS INDICATED SOUTHWEST FLOW TAKING OVER...SO THIS IS A BIT OF A CHANGE IN SOLUTIONS. THEREFORE...LOWERED TEMPERATURES A FEW DEGREES WITH HIGHS IN THE 70S ACROSS MOST OF THE AREA TO NEAR 80 OVER FAR WESTERN CARBON COUNTY. WARMER AIR WILL LIKELY MAKE IT INTO CARBON COUNTY...BUT THE REST OF THE AREA WILL BE COOLER THAN NORMAL WITH ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS AND TSTORMS. INCREASED POP BETWEEN 40 TO 55 PERCENT ALONG AND EAST OF THE LARAMIE RANGE. CAN NOT RULE OUT ANOTHER ROUND OF SEVERE THUNDERSTORMS EAST OF THE LARAMIE RANGE AS WELL...ESPECIALLY WITH SOME COOLER AIR ALOFT MOVING BACK INTO THE FORECAST AREA WHICH WILL RESULT IN HIGHER CAPE VALUES AND LI/S BELOW -5C. CONDITIONS WILL BEGIN TO IMPROVE ON WEDNESDAY AS DRIER AIR MOVES INTO CENTRAL WYOMING...GREATLY LIMITING TSTORM DEVELOPMENT. IN FACT...THE 00Z GFS SHOWS THIS DRIER AIR MOVING TOWARDS THE NEBRASKA BORDER BY MIDDAY WITH DEW POINTS LOWERING INTO THE MID TO UPPER 30S BY MID AFTERNOON. BELIEVE THIS IS TOO AGGRESSIVE AND IS PRETTY TYPICAL OF THE GFS WITH LLVL MOISTURE PRESENT AND WEAK WESTERLY FLOW. KEPT SHOWERS AND TSTORMS IN THE FORECAST WITH POP BETWEEN 20 TO 30 PERCENT ACROSS MOST LOCATIONS. TEMPERATURES WILL INCREASE TO AROUND NORMAL WITH HIGHS IN THE 80S OUTSIDE OF THE MOUNTAINS. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 440 AM MDT MON JUN 23 2014 WARM AND UNSETTLED CONDITIONS WILL CONTINUE THURSDAY AND FRIDAY AS AN UPPER TROF ALONG THE WEST COAST MOVES EAST DURING THAT TIME. CHANCES FOR MAINLY LATE DAY CONVECTION WILL REMAIN THROUGH FRIDAY AS WEAK IMPULSES PASS BY AHEAD OF THIS SYSTEM. THE MAIN UPPER TROF AXIS WILL THEN PASS ACROSS THE REGION LATE FRIDAY AND LEAVE A RATHER DRY ZONAL FLOW IN ITS WAKE FOR SATURDAY AND SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING) ISSUED AT 1145 AM MDT MON JUN 23 2014 EXPECT ANOTHER ACTIVE AFTERNOON OF TSTORM ACTIVITY...WITH BEST CHANCES ALONG AND EAST OF THE LARAMIE RANGE. VFR CONDITIONS WILL PREVAIL WITH THE EXCEPTION OF MVFR INVOF TSTORMS. THERE IS A SLIGHT RISK FOR GUSTY OUTFLOW WINDS TO 50 KT...HAIL AND HEAVY RAIN FROM CHEYENNE TO SIDNEY. THE CONVECTION WILL LIKELY LINGER THROUGH 03Z IN SOUTHEAST WY AND 06Z FOR THE NEB PANHANDLE. WITH MOIST BOUNDARY LAYER AND LIGHT WINDS...THERE IS THE POTENTIAL FOR MVFR CONDITIONS ACROSS THE PLAINS. && .FIRE WEATHER... ISSUED AT 219 AM MDT MON JUN 23 2014 NO FIRE WEATHER CONCERNS ANTICIPATED THIS WEEK WITH MINIMUM DAYTIME HUMIDITIES ABOVE 20 PERCENT ACROSS MOST AREAS...AND EVEN ABOVE 40 PERCENT ACROSS THE HIGH PLAINS THROUGH THE MIDDLE OF THE WEEK. IN ADDITION...SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH WEDNESDAY BRINGING A GOOD CHANCE OF WETTING RAINS TO MOST AREAS EAST OF THE LARAMIE VALLEY. SOME DRIER AIR WILL PUSH INTO SOUTHEAST WYOMING BY LATE THIS WEEK...BUT DO NOT EXPECT CRITICAL FIRE WEATHER CONDITIONS AT THIS TIME. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...FINCH SHORT TERM...TJT LONG TERM...EMANUEL AVIATION...JAMSKI FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1120 AM MDT MON JUN 23 2014 .UPDATE... ISSUED AT 1112 AM MDT MON JUN 23 2014 MOIST AIRMASS IS IN PLACE ACROSS THE PLAINS THIS MORNING WITH SCATTERED AREAS OF LOW CLOUDS. MODELS SHOW SFC WINDS VEERING TO THE EAST BY THIS AFTN WHICH INCREASES THE BULK SHEAR TO 45-50 KTS OFF THE RUC BY THIS AFTN. AFTN INSTABILITY IS SIMILAR TO YESTERDAY WITH THE HIGHEST VALUES (1000-1500 J/KG) IN AREAS ALONG THE COLORADO BORDER. SPC EXTENDED THE SLIGHT RISK NORTHWARD INTO THE SOUTHERN PANHANDLE AND LARAMIE COUNTY WITH THE MORNING UPDATE. COULD VERY WELL BE A REPEAT OF YESTERDAY WITH A FEW MARGINALLY SVR STORMS ALONG THE COLORADO BORDER...BUT MORE NUMEROUS ACROSS NORTHEASTERN COLORADO. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 440 AM MDT MON JUN 23 2014 CURRENT IR SATELLITE LOOP SHOWS MOSTLY CLEAR SKIES OVER THE FORECAST AREA WITH SOUTHEAST WYOMING IN BETWEEN UPPER LEVEL SHORT WAVE ACTIVITY EARLY THIS MORNING. THE NEXT SHORTWAVE IS CURRENTLY MOVING SOUTHEAST ACROSS NORTHEAST WYOMING WITH SHOWERS REDEVELOPING ALONG A LINE FROM NEWCASTLE NORTHWARD TOWARDS DEVILS TOWER. MOST MODELS HAVE BEEN TOO AGGRESSIVE WITH THIS SHORTWAVE...SHOWING IT DIGGING SOUTHWARD ACROSS THE AREA TONIGHT...BUT THAT HAS YET TO HAPPEN. THE NAM SEEMS TO BE INITIALIZING THE BEST...SO WILL MAINLY FOLLOW THE 00Z AND 06Z RUNS OVER THE NEXT 24 HOURS. THE NAM SHOWS BANDS OF RAIN SHOWERS DEVELOPING OVER CONVERSE AND NIOBRARA COUNTIES EARLY THIS MORNING AS THE SHORTWAVE DISTURBANCE PUSHES ACROSS EASTERN WYOMING AND INTO THE WESTERN DAKOTAS. THIS SEEMS MORE REALISTIC GIVEN CURRENT OBS ACROSS THE AREA. THE NAM ALSO SHOWS MOST OF THE AFTERNOON SHOWERS AND TSTORMS TODAY FURTHER TO THE SOUTH NEAR THE COLORADO BORDER...BUT THIS IS ALSO CONSISTENT WITH THE OTHER MODELS WHICH SHOW A SIMILAR SOLUTION. LOWERED POP UP NORTH TO AROUND 30 PERCENT AFTER MID TO LATE MORNING...AND INCREASED AREAS ALONG AND JUST NORTH OF THE I80 CORRIDOR IN THE AFTERNOON. EXPECT SIMILAR CONDITIONS TODAY WITH COOLER THAN NORMAL DAYTIME TEMPERATURES BUT ALSO PLENTY OF INSTABILITY...ESPECIALLY WITH THE CLEARING SKIES EARLY THIS MORNING WHICH WILL ALLOW MAXIMUM SURFACE HEATING TODAY. STILL EXPECT A SOMEWHAT HIGHER SEVERE WEATHER THREAT TODAY COMPARED TO YESTERDAY...BUT THERE IS CONCERN OVER CURRENT MODEL SOUNDINGS WHICH SHOW HIGHER LI/S AND LOWER CAPE VALUES LATE IN THE AFTERNOON DUE TO MID TO UPPER LEVEL WARMING. CAPE VALUES STILL AROUND 1500 TO 2500 J/KG EARLY IN THE AFTERNOON BUT QUICKLY LOWER THROUGH MID AFTERNOON...MEANING EITHER CONVECTION WILL START PRETTY EARLY TODAY OR IT WILL BE LIMITED IN COVERAGE THROUGH THIS AFTERNOON. BELIEVE EARLIER CONVECTION INITIATION IS MORE LIKELY GIVEN CURRENT PROFILES...WITH ACTIVITY TRANSITIONING TO RAIN SHOWERS BY LATE IN THE AFTERNOON. THUNDERSTORMS WILL BE MULTICELLULAR IN NATURE WITH TRAINING ALONG OUTFLOW BOUNDARIES AND SOME PROPAGATION EXPECTED...DUE TO DECENT 40 TO 50 KNOT DEEP LAYER SHEAR. LOCALLY HEAVY RAINFALL AND FLASH FLOODING IS POSSIBLE AS WELL. ON TUESDAY...MODELS NOW SHOW WEST TO NORTHWEST FLOW ALOFT CONTINUING OVER THE AREA WITH A WEAK RIDGE AXIS REMAINING TO THE EAST. YESTERDAY...MODELS INDICATED SOUTHWEST FLOW TAKING OVER...SO THIS IS A BIT OF A CHANGE IN SOLUTIONS. THEREFORE...LOWERED TEMPERATURES A FEW DEGREES WITH HIGHS IN THE 70S ACROSS MOST OF THE AREA TO NEAR 80 OVER FAR WESTERN CARBON COUNTY. WARMER AIR WILL LIKELY MAKE IT INTO CARBON COUNTY...BUT THE REST OF THE AREA WILL BE COOLER THAN NORMAL WITH ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS AND TSTORMS. INCREASED POP BETWEEN 40 TO 55 PERCENT ALONG AND EAST OF THE LARAMIE RANGE. CAN NOT RULE OUT ANOTHER ROUND OF SEVERE THUNDERSTORMS EAST OF THE LARAMIE RANGE AS WELL...ESPECIALLY WITH SOME COOLER AIR ALOFT MOVING BACK INTO THE FORECAST AREA WHICH WILL RESULT IN HIGHER CAPE VALUES AND LI/S BELOW -5C. CONDITIONS WILL BEGIN TO IMPROVE ON WEDNESDAY AS DRIER AIR MOVES INTO CENTRAL WYOMING...GREATLY LIMITING TSTORM DEVELOPMENT. IN FACT...THE 00Z GFS SHOWS THIS DRIER AIR MOVING TOWARDS THE NEBRASKA BORDER BY MIDDAY WITH DEWPOINTS LOWERING INTO THE MID TO UPPER 30S BY MID AFTERNOON. BELIEVE THIS IS TOO AGGRESSIVE AND IS PRETTY TYPICAL OF THE GFS WITH LLVL MOISTURE PRESENT AND WEAK WESTERLY FLOW. KEPT SHOWERS AND TSTORMS IN THE FORECAST WITH POP BETWEEN 20 TO 30 PERCENT ACROSS MOST LOCATIONS. TEMPERATURES WILL INCREASE TO AROUND NORMAL WITH HIGHS IN THE 80S OUTSIDE OF THE MOUNTAINS. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 440 AM MDT MON JUN 23 2014 WARM AND UNSETTLED CONDITIONS WILL CONTINUE THURSDAY AND FRIDAY AS AN UPPER TROF ALONG THE WEST COAST MOVES EAST DURING THAT TIME. CHANCES FOR MAINLY LATE DAY CONVECTION WILL REMAIN THROUGH FRIDAY AS WEAK IMPULSES PASS BY AHEAD OF THIS SYSTEM. THE MAIN UPPER TROF AXIS WILL THEN PASS ACROSS THE REGION LATE FRIDAY AND LEAVE A RATHER DRY ZONAL FLOW IN ITS WAKE FOR SATURDAY AND SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 440 AM MDT MON JUN 23 2014 MAINLY VFR TODAY OTHER THAN SOME PATCHY LOW VSBYS IN THE LARAMIE VALLEY THIS MORNING DUE TO FOG. SCTD SHOWERS AND TSTRMS DEVELOPING THIS AFTERNOON AND CONTINUING INTO THIS EVENING WITH ASSOCIATED LOWER VSBYS. SOME MVFR CIGS/VSBYS MAY DEVELOP OVER PARTS OF THE PLAINS LATER TONIGHT AS WEAK UPSLOPE FLOW DEVELOPS. && .FIRE WEATHER... ISSUED AT 219 AM MDT MON JUN 23 2014 NO FIRE WEATHER CONCERNS ANTICIPATED THIS WEEK WITH MINIMUM DAYTIME HUMIDITIES ABOVE 20 PERCENT ACROSS MOST AREAS...AND EVEN ABOVE 40 PERCENT ACROSS THE HIGH PLAINS THROUGH THE MIDDLE OF THE WEEK. IN ADDITION...SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH WEDNESDAY BRINGING A GOOD CHANCE OF WETTING RAINS TO MOST AREAS EAST OF THE LARAMIE VALLEY. SOME DRIER AIR WILL PUSH INTO SOUTHEAST WYOMING BY LATE THIS WEEK...BUT DO NOT EXPECT CRITICAL FIRE WEATHER CONDITIONS AT THIS TIME. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...FINCH SHORT TERM...TJT LONG TERM...RE AVIATION...RE FIRE WEATHER...TJT