000
FXUS64 KMRX 201130
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
730 AM EDT MON JUL 20 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 729 AM EDT MON JUL 20 2026
- ISOLATED TO SCATTERED SHOWERS AND STORMS TO CONTINUE THIS
AFTERNOON AND EVENING. A FEW STRONG TO MARGINALLY SEVERE STORMS
ARE POSSIBLE AND COULD PRODUCE GUSTY WINDS AND LOCALIZED
FLOODING.
- POSSIBLE STRONG COLD FRONTAL PASSAGE TOMORROW EVENING INTO
WEDNESDAY BEARS WATCHING FOR SEVERE WEATHER POTENTIAL.
- BELOW NORMAL TEMPERATURES AND DRIER AIR WILL FOLLOW BEYOND
WEDNESDAY. PRECIPITATION RETURNS NEXT WEEKEND.
DISCUSSION
ISSUED AT 123 AM EDT MON JUL 20 2026
THE LARGE SCALE PATTERN CAN BE CLASSIFIED BY RIDGING GENERALLY
CENTERED OVER THE FOUR CORNERS REGION AND INTERMOUNTAIN WEST THE
NEXT COUPLE OF DAYS, FOLLOWED BY WEAK NWLY FLOW OVER US WITH
TROUGHING TO THE NORTH AND SUBSEQUENT SHORTWAVES CYCLING THROUGH. A
TROPICAL DEPRESSION BY THE FLORIDA PENINSULA WILL BECOME ALMOST
STATIONARY UNTIL IT GETS PICKED UP AND EVENTUALLY DRIFTS WESTWARD. A
STOUT SHORTWAVE EXPECTED TO DIVE SE ACROSS THE NORTHERN GREAT LAKES
BEFORE CURVING UP AROUND THE U.S. BORDER LATE TOMORROW INTO
WEDNESDAY, WILL BRING OUR NEXT FRONTAL SYSTEM ACROSS THE AREA.
FOLLOWING THAT, WE'LL STILL BE SITUATED EAST OF UPPER RIDGE INTO THE
LATTER PART OF THE WEEK AND INTO THE WEEKEND.
DIURNAL THUNDERSTORM ACTIVITY CONTINUES TODAY MUCH LIKE THE PAST
COUPLE OF DAYS, EXCEPT THE MOUNTAINOUS TERRAIN WILL LIKELY SEE THE
BEST CHANCE DURING THE AFTERNOON AND EVENING. THE WEST TO EAST
BOUNDARY THAT WAS DRAPED NEAR THE TN AND VA BORDER YESTERDAY, WILL
BE SITUATED A BIT FURTHER NORTH TODAY. A FEW STRONG STRONG TO SEVERE
STORMS ARE POSSIBLE DUE TO MODERATE CAPE, BUT SHEAR WILL CONTINUE TO
BE WEAK. THE MAIN THREAT WITH ANY STRONGER STORM WILL BE LOCALIZED
GUSTY WINDS. HEAVY RAIN IS ALSO EXPECTED AS PWATS ARE AROUND 2
INCHES AND THIS MAY LEAD TO ISOLATED FLOODING FOR SOME. ANY AREA
THAT SEES REPEAT HEAVY SHOWERS THROUGH THIS EVENING WILL BE MOST AT
RISK FOR FLOODING. AGAIN, GUSTY WIND THREAT AND FLOOD THREAT WILL BE
ISOLATED. THE STRONGER STORM AND FLOODING THREAT WILL LIKELY BE FOR
AREAS EAST OF I-75.
ATTENTION TURNS TO TOMORROW INTO WEDNESDAY WITH A POTENTIAL STRONG
COLD FRONTAL PASSAGE. SPC INTRODUCED A SLIGHT RISK FOR SEVERE
WEATHER FOR THE NORTHERN PART OF THE CWA AS OF THIS DISCUSSION. THE
MAIN THREATS ARE DAMAGING WINDS AND HEAVY RAIN THAT MAY LEAD TO
FLASH FLOODING. SECONDARY THREATS THAT CANNOT BE RULED OUT ARE A
COUPLE OF TORNADOS AND POSSIBLE SMALL HAIL. THE TORNADO THREAT WILL
ULTIMATELY DEPEND ON WHETHER STORMS REMAIN SURFACE-BASED DURING THE
OVERNIGHT HOURS OR BECOME ELEVATED. TIMING WILL DEFINITELY PLAY A
ROLE AS TO WHEN THE MAIN LINE ARRIVES AND WHAT IT MEANS FOR OUR
AREA, SO THERE'S STILL SOME UNCERTAINTY. ONE FACTOR THAT MODELS HAVE
CONSISTENTLY SHOWN THE PAST COUPLE OF NIGHTS IS INCREASED SHEAR.
FOLLOWING THE MID-WEEK COLD FRONT, THURSDAY WILL BE VERY NICE WITH
LOW TO MID 80S HIGHS AND DEW POINTS IN THE 60S UNDER HIGH PRESSURE.
TEMPERATURES RISE A COUPLE OF DEGREES INTO THE WEEKEND, BUT FOR THE
MOST PART REMAIN BELOW NORMAL. A SHORTWAVE CYCLING THE TOP OF THE
UPPER RIDGE FRIDAY INTO SATURDAY, MAY BRING PRECIPITATION CHANCES
BACK TO THE AREA AND UNFORTUNATELY INCREASED DEW POINTS YET AGAIN. A
POSSIBLE BOUNDARY THAT COULD GET HUNG UP TO OUR SOUTH MAY COMPLICATE
THINGS.
AVIATION
(12Z TAFS)
ISSUED AT 729 AM EDT MON JUL 20 2026
FOG IS PREVALENT ACROSS MANY TERMINALS THIS MORNING, HOWEVER NO
DENSE FOG IS BEING OBSERVED. IFR CLOUD DECK AT TRI WILL GRADUALLY
LIFT AND SCATTER OVER THE NEXT 2 OR SO HOURS. VFR CONDITIONS
EXPECTED LATER THIS MORNING, WITH ANOTHER ROUND OF DIURNAL STORMS,
THOUGH THEY ARE MORE LIKELY TO FORM OVER THE HIGH TERRAIN FIRST,
WITH UNCERTAIN COVERAGE AND IMPACTS IN THE VALLEY. PATCHY FOG
AGAIN LIKELY TONIGHT.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 92 75 93 76 / 40 10 30 40
KNOXVILLE MCGHEE TYSON AIRPORT, TN 90 74 90 74 / 30 30 40 80
OAK RIDGE, TN 89 73 90 73 / 40 20 50 90
TRI CITIES AIRPORT, TN 88 70 87 70 / 40 40 70 100
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...KS
AVIATION...WELLINGTON
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