wsuffa
Touchdown! Greaser!
This is a thought piece for discussion about weather ADM. Time to play Monday Morning Quarterback:
So, let's suppose that you wanted to make a trip yesterday (Sunday) from the DC area to the Dayton, OH area. Goal is to have lunch with a friend in the area. You must be back sometime Sunday as you have a meeting commitment for work Monday AM.
Plan would be to launch out of DC area around 8 AM, flying time of 2:15-2:45 (depending on route and headwinds). Normal ATC routing for GPS-equipped is LDN->EKN->PKB->XUB->Destination. Since you have plenty of fuel, you can go north (to MGW->AIR, then over the V214 corridor and/or APE), or you can head south over the normal route to Cincinnati (Over CRW thence YRK thence FLM thence Destination)... but you need to make the choice before launching as the routing is enough different that it's impractical to backtrack.
You're in a well equipped IFR GA aircraft with XM Weather, IFR-certified GPS/RNAV, and stormscope aboard. You are IFR current (IPC within the last 2 weeks) and well rested for the day. Plane has 5+ hours of fuel. You have Foreflight (fully charged) and being a bit retentive about this you also have paper charts across the route. You've planned for 10,000 or 12,000 outbound - the plane is equipped with oxygen and canulas (you also have a pulse-ox) & is turbocharged for flight up to FL200.
You've been watching the forecasts (TAF, area forecast, and AFD) as well as observing the weather models (maps available on Wunderground.com). You're not too worried about showers or VCSH, but you won't fly in/near convection.
Decision time is 7 AM.
Just for fun, let's also say you also plan to take a passenger that's ok with GA unless conditions are bad or very bumpy, in which case they would rather land NOW.
Here's the forecast & discussion from the night before. The model maps for 12Z-18Z show a fairly wide area along the route of flight with little to no precip during the period. After 18Z, the area fills in with precip.
And the AFD at decision time. Models show a large "blob" on the north side of the Dayton area for arrival time, it moves eastward centered in your flight path for departure time. Nexrad at decision time shows a line of precip with imbedded cells from just north of LEX to roughly XUB moving northeast:
Area forecast lists tops at or above 20,000.
And the TAF (KPKB ) and AFD for the West Virgnia enroute sector:
Here's the forecast at decision time for CMH (your return flight would pass through CMH airspace between 1730z and 1830z):
Would you go?
So, let's suppose that you wanted to make a trip yesterday (Sunday) from the DC area to the Dayton, OH area. Goal is to have lunch with a friend in the area. You must be back sometime Sunday as you have a meeting commitment for work Monday AM.
Plan would be to launch out of DC area around 8 AM, flying time of 2:15-2:45 (depending on route and headwinds). Normal ATC routing for GPS-equipped is LDN->EKN->PKB->XUB->Destination. Since you have plenty of fuel, you can go north (to MGW->AIR, then over the V214 corridor and/or APE), or you can head south over the normal route to Cincinnati (Over CRW thence YRK thence FLM thence Destination)... but you need to make the choice before launching as the routing is enough different that it's impractical to backtrack.
You're in a well equipped IFR GA aircraft with XM Weather, IFR-certified GPS/RNAV, and stormscope aboard. You are IFR current (IPC within the last 2 weeks) and well rested for the day. Plane has 5+ hours of fuel. You have Foreflight (fully charged) and being a bit retentive about this you also have paper charts across the route. You've planned for 10,000 or 12,000 outbound - the plane is equipped with oxygen and canulas (you also have a pulse-ox) & is turbocharged for flight up to FL200.
You've been watching the forecasts (TAF, area forecast, and AFD) as well as observing the weather models (maps available on Wunderground.com). You're not too worried about showers or VCSH, but you won't fly in/near convection.
Decision time is 7 AM.
Just for fun, let's also say you also plan to take a passenger that's ok with GA unless conditions are bad or very bumpy, in which case they would rather land NOW.
Here's the forecast & discussion from the night before. The model maps for 12Z-18Z show a fairly wide area along the route of flight with little to no precip during the period. After 18Z, the area fills in with precip.
FTUS41 KILN 162300
TAFDAY
TAF
KDAY 162338Z 1700/1724 18009KT P6SM FEW050 BKN250
FM170700 20008KT P6SM VCSH BKN070
FM171500 21012KT P6SM -SHRA VCTS BKN050CB
FM171800 23011KT P6SM SCT050=
000
FXUS61 KILN 170150
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
950 PM EDT SAT JUN 16 2012
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL ENTER THE OHIO VALLEY FROM THE
MIDWEST TONIGHT...BREAKING DOWN AN ESTABLISHED UPPER LEVEL RIDGE.
THE ATMOSPHERE WILL QUICKLY REESTABLISH THIS RIDGE LATER ON MONDAY
AND HIGH PRESSURE WILL PREVAIL THROUGH AT LEAST MID WEEK.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
BY DAYBREAK...THERE SHOULD BE ENOUGH CLOUD COVER OVER CWA AND
OHIO VALLEY TO REMOVE THE ADDED KICK OF DIURNAL HEATING. WHILE
STORMS WILL BE PRESENT FROM THE MORNING INTO THE
AFTERNOON...THERE MAY BE A MARKED LACK OF ORGANIZED CONVECTION.
THE H5 RIDGE IS SUFFICIENTLY BEATEN DOWN BY THE EVENING AND THE
SHOWERS WILL DIMINISH IN COVERAGE AND STRENGTH THROUGH THE
OVERNIGHT HOURS. SURFACE FLOW NEVER SWITCHES FROM SOUTHWEST AND
THERE MAY BE ENOUGH CONVERGENCE IN THE LOWER LEVELS TO KEEP A
SHOWER THREAT GOING THROUGH DAYBREAK. THE CONVERGENT AREA WILL
LIFT NORTHEAST ON MONDAY IN THE MEAN FLOW AND A LINGERING SHOWER
EARLY IN THE DAY CANNOT BE RULED OUT...PRIMARILY IN NERN CWA.
WHILE LIKELY POPS ARE EXPRESSED IN THE FORECAST AT 18Z SUNDAY...I
WAS NOT CONVINCED OF THAT AT THAT HOUR...BUT I HAVE LITTLE DOUBT
THAT AN AREA OF SHOWERS WILL MOVE FROM NW TO SE OVER CWA DURING
THE DAY AND I AM KEEPING THE GRID UNCHANGED.
TEMPERATURES WERE NOT CHANGED MUCH FROM PREVIOUS FORECAST.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
EXPECT QUIESCENT CONDITIONS FOR THE EARLY PART OF THE TAF PERIOD.
BEYOND THAT CONFIDENCE IN FORECAST IS NOT PARTICULARLY HIGH
ESPECIALLY IN TERMS OF WHEN WEATHER MAY IMPACT TERMINALS. APPEARS
THAT ELEVATED SHOWERS AND THUNDERSTORMS WILL START DEVELOPING
AFTER 06Z. INITIALLY THIS ACTIVITY SHOULD BE ISOLATED TO
SCATTERED. COVERAGE WILL INCREASE AFTER 12Z. HAVE OPTED TO USE
VCSH IN THE TAFS TO INDICATE THIS CHANCE. AT THIS POINT GUIDANCE
IS SUGGESTING THAT A MORE ROBUST LINE OF SHOWERS AND STORMS MAY
MOVE THROUGH DURING THE DAY. HAVE FORECAST A 3 HOUR WINDOW OF VCTS
TO INDICATE WHEN THE BETTER CHANCE OF CONVECTION IS EXPECTED.
OUTLOOK...SCATTERED THUNDERSTORMS POSSIBLE SUNDAY NIGHT AND MONDAY.
And the AFD at decision time. Models show a large "blob" on the north side of the Dayton area for arrival time, it moves eastward centered in your flight path for departure time. Nexrad at decision time shows a line of precip with imbedded cells from just north of LEX to roughly XUB moving northeast:
Area forecast lists tops at or above 20,000.
FTUS41 KILN 171100
TAFDAY
TAF
KDAY 171133Z 1712/1812 19010KT P6SM VCSH BKN060
FM171500 20014G20KT P6SM -SHRA VCTS BKN050CB
FM171900 21012G20KT P6SM BKN050
FM180000 20006KT P6SM BKN070=
(Note that the forecast for KFFO showed VCTS from roughly 12Z to 19Z)
000
FXUS61 KILN 171043
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
643 AM EDT SUN JUN 17 2012
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND THUNDERSTORMS TO
THE AREA TODAY AND POSSIBLY AGAIN ON MONDAY. RIDGING WILL THEN BUILD
BACK ACROSS OUR AREA MONDAY NIGHT...AND WILL REMAIN IN PLACE OVER
THE REGION THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN EMBEDDED SHORTWAVE SOUTH OF A STORM SYSTEM OVER ONTARIO WILL
PUSH EAST TOWARD THE OHIO VALLEY TODAY. AN ENHANCED LOW LEVEL JET
AHEAD OF THIS SHORTWAVE WILL COMBINE WITH AMPLE ELEVATED
INSTABILITY AND PRECIPITABLE WATER VALUES OF OVER 1.5 INCHES TO
PRODUCE NUMEROUS SHOWERS AND THUNDERSTORMS THIS MORNING THROUGH
THE AFTERNOON. NEW RUNS OF HI RES MODELS ARE IN AGREEMENT OF
BRINGING THE NOSE OF THE LOW LEVEL JET TO OUR WESTERN ZONES BY
DAYBREAK. ELEVATED CONVECTION WILL LIKELY INITIATE BY THAT TIME.
THIS ACTIVITY WILL FILL IN AND SPREAD EASTWARD...ALONG WITH THE
FORCING CAUSED BY THE JET. TIMING OF PRECIPITATION HAS SHIFTED
WITH THE NEWER MODEL RUNS AND IT NOW APPEARS THAT THE MAIN
CONVECTION FROM THIS EVENT WILL OCCUR A BIT EARLIER. HAVE THE
BEST CHANCE POPS NOW ACROSS THE WEST JUST AFTER SUNRISE THIS
MORNING...AND IN THE EAST BY THE LATE MORNING HOURS.
AFTER THIS BAND OF CONVECTION PASSES...THERE MAY BE SOME CLEARING
AND DESTABILIZATION FOR SOME ADDITIONAL SCATTERED SHOWERS AND
THUNDERSTORMS TO OCCUR LATER THIS AFTERNOON.
HAVE THEREFORE FORECAST A ROUND OF CHANCE POPS THIS AFTERNOON
ACROSS THE AREA. IF CLOUD COVER DOES PERSIST A BIT LONGER INTO THE
EARLY AFTERNOON...THE ATMOSPHERE MAY NOT HAVE ENOUGH TIME TO
RECOVER FROM THIS MORNINGS CONVECTION. THUS THIS AFTERNOON POPS
MAY NEED SOME ADJUSTMENTS ONCE THE INITIAL CONVECTION MOVES
THROUGH THE AREA.
THE TEMPERATURE FORECAST WAS SOMEWHAT UNCERTAIN BASED ON TIMING
AND LOCATION OF PRECIPITATION. HAVE FORECAST BASED ON THE IDEA
THAT SOME CLEARING WILL OCCUR TO THE WEST THIS AFTERNOON. SO WITH
THAT IN MIND HAVE FORECAST A REBOUND INTO THE UPPER 80S IN THE
WEST...WHILE KEEPING THE EASTERN ZONES IN THE LOW 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
ANY REMAINING CONVECTION WILL BEGIN TO WANE AS WE LOSE DIURNAL
HEATING. FORCING ASSOCIATED WITH THE PASSING DISTURBANCE WILL
SHIFT EASTWARD...AND THEREFORE A QUICK DECLINE IN POPS FROM WEST
TO EAST WILL OCCUR IN THE EVENING. THE FORECAST AREA WILL THEN BE
IN A LULL BETWEEN THE DEPARTING DISTURBANCE...AND THE APPROACH OF
ANOTHER WEAKER DISTURBANCE. OPTED TO GO DRY LATE TONIGHT THROUGH
MONDAY MORNING. SOME CLEARING IS EXPECTED SUNDAY NIGHT...HOWEVER
TO WHAT EXTENT IS DIFFICULT TO ASCERTAIN AT THIS TIME.
AS THE NEXT WEAK SHORTWAVE PASSES ACROSS THE OHIO
VALLEY MONDAY...SOME THUNDERSTORM DEVELOPMENT WILL BE
POSSIBLE AS PLENTY OF SURFACE INSTABILITY WILL BE IN PLACE BY THE
AFTERNOON. HAVE FORECAST 20 TO 30 POPS FOR NOW. HOWEVER...GUIDANCE
HAS BEEN TRENDING HIGHER THAN THIS IN RECENT RUNS. WITH THE
ADDITIONAL CLOUD COVER EXPECTED FROM THE SECOND DISTURBANCE...KEPT
MAX TEMPERATURES BELOW THE 90 DEGREE MARK FOR MOST OF THE AREA.
UPPER LEVEL RIDGING WILL BUILD ACROSS THE REGION STARTING MONDAY
AFTERNOON AND WILL CONTINUE TO POSITION ITSELF OVER OUR AREA INTO
TUESDAY. TEMPERATURES MONDAY NIGHT WILL RUN SEVERAL DEGREES
ABOVE NORMAL AS WILL MAXIMUM TEMPERATURES TUESDAY. MOST OF THE
AREA WILL SEE TEMPERATURES IN THE LOW 90S BY TUESDAY AFTERNOON.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
ACROSS PARTS OF THE AREA THIS MORNING. THE INITIAL AREA OF PCPN IS
CURRENTLY PUSHING EAST OF THE AREA BUT A NARROW LINE OF ISOLATED
THUNDERSTORMS ALONG THE INDIANA/OHIO BORDER IS WORKING ITS WAY EAST
AND MAY AFFECT THE WESTERN TAF SITES THROUGH THE FIRST HOUR OR TWO
OF THE TAF PERIOD. ONCE THESE MOVE THROUGH...WE COULD SEE A BRIEF
BREAK BEFORE UPPER LEVEL SHORT WAVE MOVES IN LATER THIS MORNING
INTO THIS AFTERNOON. INSTABILITY WILL BE AT LEAST SOMEWHAT AFFECTED
BY THE AMOUNT OF DEBRIS CLOUDS REMAINING FROM THE CONVECTION THIS
MORNING. WOULD THINK THE BEST CHANCE FOR ANY REDEVELOPMENT WOULD BE
FROM LATE MORNING THROUGH MID AFTERNOON. DUE TO THE
UNCERTAINTY THOUGH...WILL CONTINUE TO COVER THE THREAT WITH A
PREVAILING -SHRA AND A VCTS. WE SHOULD THEN SEE ANOTHER BREAK IN
THE PCPN AS WE GET ON THE BACK SIDE OF THE SHORT WAVE LATER THIS
AFTERNOON INTO THIS EVENING. MODELS ARE CONTINUING TO HINT AT THE
POSSIBILITY OF SOME ISOLATED SHOWERS LATER TONIGHT...BUT FORCING
APPEARS FAIRLY WEAK SO WILL HOLD OFF ON INCLUDING ANYTHING IN THE
TAFS.
OUTLOOK...SCATTERED THUNDERSTORMS POSSIBLE MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
And the TAF (KPKB ) and AFD for the West Virgnia enroute sector:
FTUS41 KRLX 171100
TAFPKB
TAF
KPKB 171121Z 1712/1812 16006KT P6SM BKN030
FM171400 19006KT P6SM BKN040
FM171700 20006KT P6SM VCTS BKN060CB
FM172000 21007KT P6SM SHRA VCTS BKN040CB
FM172300 20007KT 4SM SHRA VCTS OVC025CB
FM180200 21006KT 6SM SHRA VCTS BKN035CB
FM180400 20006KT 5SM BR VCTS BKN050CB=
000
FXUS61 KRLX 171046
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
646 AM EDT SUN JUN 17 2012
.SYNOPSIS...
WARM FRONT CROSSES THIS MORNING. AN UPPER LEVEL DISTURBANCE CROSSES
THIS AFTERNOON AND TONIGHT...AND ANOTHER CROSSES MONDAY. UPPER
RIDGE TAKES HOLD FOR MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
WARM FRONT OVER W EDGES OF FCST AREA EARLY THIS MORNING EXTENDS N
INTO NRN LOWER MI...WHERE IT IS OCCLUDED BY A COLD FRONT THAT
EXTENDS SW INTO THE MID MISSISSIPPI VALLEY. FIRST PROBLEM OF THE
DAY IS WHETHER PRECIPITATION WILL FIRE UP ALONG THE WARM FRONT EARLY
THIS MORNING AS IS TYPICAL THIS TIME OF DAY GIVEN A STRONG DEW POINT
/ THETA E GRADIENT IN THE LOWER LEVELS. NEAR TERM MODELS HAVE
BACKED OFF ON SAID DEVELOPMENT. LOW LEVEL CONVERGENCE ALONG THE
WARM FRONT IS SHALLOW...AND DISAPPEARS BY THE TIME ONE REACHES H85.
NONETHELESS...SCATTERED THUNDERSTORMS HAVE BEGUN TO FIRE EITHER SIDE
OF THE OHIO RIVER JUST W OF THE FCST AREA.
THE ABSENCE OF MORNING DEVELOPMENT WOULD ALLOW FOR ADDITIONAL
SURFACE HEATING TO FUEL AFTERNOON DEVELOPMENT OF CONVECTION AHEAD OF
AN UPPER LEVEL S/W TROUGH APPROACHING FROM THE W THIS
AFTERNOON...THE SECOND PROBLEM OF THE DAY. WITH THE SURFACE COLD
FRONT DISSIPATING...AND THE BEST UPPER LEVEL FORCING HEADED JUST N
OF THE FCST AREA...BEST INSTABILITY IS SHOWN W AND N OF THE FCST
AREA THROUGH SUNSET...KEEPING SEVERE THREAT TO A MINIMUM WITHIN THE
FCST AREA. FASTER STORM MOTION COMPARED WITH SATURDAY WILL ALSO
HELP TO MITIGATE THE FLOOD THREAT ASSOCIATED WITH SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND THIS EVENING.
THE SHOWERS AND THUNDERSTORMS MOVE ON E OVERNIGHT AND DIMINISH IN
AREA COVERAGE AFTER SUNSET...BUT AREAS OF FOG ARE LIKELY TO FORM
TONIGHT WHERE IT RAINS FROM THIS AFTERNOON ON.
WITH HIGH TEMPERATURES WITHIN THE SMALL ENVELOP OF GUIDANCE...AND
UNCERTAINTY AS TO PRECIPITATION DEVELOPMENT THIS MORNING AND HENCE
THE AMOUNT OF SUNSHINE TODAY...SAW LITTLE OR NO IMPROVEMENT
POTENTIAL ON HIGHS TODAY. DID EDGE LOWS TONIGHT UPWARD TOWARD
ADJMET GIVEN GUIDANCE ENVELOP OVERALL...DEW POINTS REMAINING HIGH
AND LESS THAN IDEAL RADIATIVE COOLING CONDITIONS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
PATCHY STRATOCU DECK AROUND THE AREA THIS MORNING WITH CIGS JUST
ABOVE 3 KFT IN SPOTS. BIGGER STORY IS SHOWERS AND THUNDERSTORMS
APPROACHING FROM THE W...WHICH COULD REACH VICINITY OF HTS AS EARLY
AS 14Z. AS THIS ACTIVITY MOVES INTO WV LATER THIS MORNING...IT WILL
TEND TO BREAK UP. HOWEVER...NEW THUNDERSTORMS WILL FIRE UP IN E
OHIO THIS AFTERNOON AND MOVE E ACROSS THE AREA LATER THIS AFTERNOON
AND TONIGHT. CODED UP SOME MVFR BUT OF COURSE...IFR WILL BE FOUND
RIGHT BENEATH ANY THUNDERSTORM.
FOG WILL FORM TONIGHT ANYWHERE IT RAINS LATER TODAY AND / OR TONIGHT
SO TOUGH TO PEG LOCATION ALTHOUGH DID HIT TYGART VALLEY HARD LATE
TONIGHT.
LIGHT SE SFC FLOW WILL BECOME LIGHT SW AS A WARM FRONT CROSSES THE
AREA THIS MORNING...AND THEN LIGHT S TO LIGHT AND VARIABLE TONIGHT.
FLOW ALOFT WILL BE LIGHT SW.
Here's the forecast at decision time for CMH (your return flight would pass through CMH airspace between 1730z and 1830z):
FTUS41 KILN 171100
TAFCMH
TAF
KCMH 171133Z 1712/1812 17008KT P6SM BKN080
FM171300 18012KT P6SM VCSH BKN060
FM171700 20012G20KT P6SM -SHRA VCTS BKN050CB
FM172200 20010KT P6SM BKN050
FM180100 19005KT P6SM BKN070=
Would you go?
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