Area Forecast Discussion
Issued by NWS Nashville, TN

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000
FXUS64 KOHX 290206 AAD
AFDOHX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NASHVILLE TN
906 PM CDT TUE JUL 28 2015

.UPDATE...
BEST INSTABILITY CONTINUING TO REMAIN ACROSS LOCATIONS APPROACHING
THE TN RIVER VALLEY REGION. ALTHOUGH CONVECTION IS WEAKENING...
WITH A BROAD AREA OF SHWRS...WITH SOME EMBEDDED TSTMS...REACHING
AS FAR E AS THE I-65 CORRIDOR AROUND 02Z...AND THE LATEST HRRR
MODEL INITIALIZING THIS OVERALL WX PATTERN BETTER...WILL GO AHEAD
WITH INCREASING SHWR/TSTM CHANCES ACROSS THESE AREAS THRU AT LEAST
MIDNIGHT...WITH NUMEROUS SHWRS/TSTMS POSSIBLE AS ONE APPROACHES
THE TN RIVER VALLEY REGION. BELIEVE THRU THE FIRST PART OF THE
EARLY MORNING HRS THAT AT LEAST SCT SHWRS...WITH SOME ISO
TSTMS...AROUND UPPER LEVEL RIDGE PERIPHERY...WILL BE POSSIBLE...
AND THUS WILL MENTION ALSO. WHILE MAKING THESE CHANGES...TWEAKED
HRLY TEMP...DEWPOINT...SKY CONDITION...AND WIND SPEED/DIRECTION GRIDS.
&&

.PREV DISCUSSION.../ISSUED 750 PM CDT TUE JUL 28 2015/

UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REMOVE MENTION OF
LATE AFTERNOON ZONE GROUPING IN ZONE FORECAST PRODUCT AND ALL
REFERENCES TO HEAT ADVISORY THAT EXPIRED AT 7 PM THIS EVENING.
WILL ALSO UPDATE THE HAZARDOUS WEATHER OUTLOOK PRODUCT TO DO
THE SAME. PER REGIONAL RADAR TRENDS...WITH SHWRS/TSTMS MOVING IN
FROM THE NW INTO LOCATIONS N OF I-40 AND W OF 1-65...AROUND
PERIPHERY OF UPPER LEVEL RIDGING DYNAMICS...WILL KEEP CHANCE POPS
ACROSS THIS REGION THRU THE MID EVENING HRS...BUT WITH DIURNAL
INFLUENCES GRADUALLY WEAKENING...DUE EXPECT AN OVERALL TREND OF
WEAKENING SHWRS/TSTMS THRU THE MID EVENING HRS ALONG WITH A
DECREASING TREND IN AREAL COVERAGE. THIS REASONING SUPPORTED BY
CONSENSUS OF SHORT RANGE MODEL SOLUTIONS. WILL KEEP A SLIGHT
CHANCE OF SHWRS/TSTMS ACROSS THE REST OF THE MID STATE THRU THE
EVENING HRS. EVEN THOUGH THERE IS SOME INDICATION IN SHORT RANGE
MODELS FOR A PREFERENCE FOR SHWR/TSTM ACTIVITY ACROSS WRN PORTIONS
OF THE MID STATE AFTER MIDNIGHT...ONLY EXPECTING ISO SHWRS/TSTMS
AT BEST...AND WILL THUS ADDRESS ALL AREAS ACROSS THE MID STATE
EXPERIENCING A SLIGHT CHANCE OF SHWRS/TSTMS AFTER MIDNIGHT. ALSO
TWEAKED HRLY TEMP...DEWPOINT...SKY CONDITION...AND WIND SPEED/DIRECTION
GRIDS. CURRENT TEMPS TRENDS SEEM IN LINE WITH FORECASTED LOW VALUES
EXPECTED OVERNIGHT AND THUS NO CHANGES NEEDED.

PREV DISCUSSION.../ISSUED 615 PM CDT TUE JUL 28 2015/

AVIATION 00Z DISCUSSION...
IMPULSE MOVING SOUTHWARD THROUGH THE MID STATE THIS EVENING. NVA
SHOULD MOVE IN AFT 03Z AND END THE OVERNIGHT CONVECTION. HRRR
CONCURS WITH RAIN FREE CONDITIONS BY 5Z. WILL OPT TO BE A LITTLE
MORE BULLISH WITH THE FOG POTENTIAL AND LOWER THE TEMPORARY VSBY
REDUCTIONS. MUCH OF THE AREA IS RAIN COOLED AND DEWPOINT SPREADS
ARE RATHER LOW.

UPPER HIGH MAY BE IN CLOSER PROXIMITY FOR TOMORROW. HOWEVER...CAPE
TO CAP RATIOS WILL BECOME FAVORABLE ONCE AGAIN IN THE AFT. WILL
INCLUDE VCNTY/CONVECTION IN TAFS AFT 18Z.

PREV DISCUSSION.../ISSUED 509 PM CDT TUE JUL 28 2015/

UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO ADD A LATE AFTERNOON
ZONE GROUPING TO THE ZONE FORECAST PRODUCT TO EMPHASIZE SCT SHWR/TSTM
CONVECTION ACROSS MID STATE. ALSO ADJUSTED HRLY TEMP...DEWPOINT...
WIND DIRECTION/SPEED...AND SKY CONDITION GRIDS.

PREV DISCUSSION.../ISSUED 236 PM CDT TUE JUL 28 2015/

DISCUSSION...
UPPER RIDGE HAS A STRONGHOLD ON MUCH OF THE AREA WITH HIGH HEAT
INDICIES PROMPTING A HEAT ADVISORY FOR A GOOD PART OF THE MID
STATE UNTIL 7 PM CDT THIS EVENING. CONVECTION HAS FIRED IN THE
AFTERNOON HEAT MAINLY ACROSS EASTERN AREAS AND ALONG THE PLATEAU
WITH MORE CONVECTION DROPPING SOUTH BOUND FROM KENTUCKY. LOOKS
LIKE A VORTICITY MAX (SHORT WAVE) WORKING DOWN FRONT SIDE OF
UPPER RIDGE. VORT MAX CURRENTLY SHOWING UP IN LATEST RUC13 RUN
NOSING JUST SOUTH OF OHIO RIVER SOUTH OF LOUISVILLE...HEADED THIS
WAY. SHORT WAVE SHOULD ENHANCE CONVECTION OVER SOUTH CENTRAL
KENTUCKY THAT WILL WORK DOWN INTO MIDDLE TENNESSEE REMAINDER OF
THE AFTERNOON AND INTO THE EVENING. MODELS KEEP SOME CONVECTION
AROUND AFTER MIDNIGHT WITH WESTERN AREAS OF THE MID STATE FAVORED.

ANOTHER HOT DAY WEDNESDAY WITH AN INCREASED CHANCE OF RAIN AS FRONT
APPROACHES FROM THE NORTHWEST. SHOWER AND THUNDERSTORMS WILL RAMP
UP WEDNESDAY EVENING AND OVERNIGHT AS FRONT WORKS INTO THE MID
STATE. SHOWER AND THUNDERSTORM CHANCES CONTINUE SOUTHEAST HALF ON
THURSDAY BUT DRY THURSDAY NIGHT AND THROUGH THE UPCOMING WEEKEND.
UPPER RIDGE THAT HAS KEPT TEMPS ABOVE NORMAL AND HEAT INDICIES
AROUND TRIPLE DIGITS WILL FINALLY RETROGRADE ALLOWING UPPER TROUGH
TO DOMINATE FRIDAY THROUGH THE WEEKEND. NEXT CHANCE FOR RAIN LOOKS
TO BE ABOUT THE MIDDLE OF NEXT WEEK.
&&

.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE      76  94  75  90 /  40  30  40  30
CLARKSVILLE    75  94  72  87 /  60  30  40  10
CROSSVILLE     71  87  72  84 /  20  30  40  50
COLUMBIA       75  93  74  91 /  60  30  40  40
LAWRENCEBURG   75  90  73  90 /  60  30  40  50
WAVERLY        75  95  73  88 /  60  30  40  10
&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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