750
FXUS64 KMRX 151138 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
738 AM EDT Sun Sep 15 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 247 AM EDT Sun Sep 15 2024

Key Messages:

1. Another warm day on tap, with highs 4-6 degrees above normal.

2. A stray shower can`t be ruled out along the southern plateau
region. But most areas see another dry day.

Discussion:

A dominant upper ridge will remain situated from the eastern Great
Lakes southward along the Appalachian chain through the short term
period more or less. Surface flow will be out of the north, with
easterly H85 flow across the southern Appalachians, resulting in dry
conditions for most all of the area. Some showers may pop up near
the TN/GA/AL border region this afternoon but suspect even then any
showers will be very isolated in nature. The easterly, downslope
flow will once again produce very warm conditions across the region
today, with highs in the TN valley expected to be several degrees
above normal, generally in the upper 80s.

Meanwhile, a weak surface low off the Georgia and South Carolina
coast is expected to gradually strengthen over the next 24 hours.
During this time it will also be shoved westward towards the coast
thanks to the aforementioned ridge, possibly pushing into the
central parts of SC by the end of the short term period. High clouds
may be on the increase heading into Monday morning as a result of
this, but any other effects (especially rainfall) would occur in the
long term period.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 247 AM EDT Sun Sep 15 2024

Key Messages:

1. Forecast highly dependent on development and evolution of a
tropical disturbance off of the Carolina coast. Very low confidence
in the details with time. Precipitation chances look best for
northeastern part of our forecast area and parts of the Appalachians.

2. Temperatures will mostly run a couple degrees above normal for
middle September with the exception of areas that will be impacted
by the tropical disturbance.

Discussion:

The long term period will depend on the evolution of new tropical
development off of the Carolina coast. NHC as of 2 AM this morning
highlights the disturbance with a 50% chance of cyclone formation.
The days of gusty winds we`ve had however, look to back off after
Monday across the higher terrain as well as the lighter gusts
elsewhere.

Even at the start of the long term early Monday, models are already
in obvious disagreement with the low pressure center off of the
Carolinas. 00Z GFS is running ahead of the other deterministic runs
with the center over land Monday morning. Beyond that until the end
of our forecast period through next Saturday - good luck! Best
chances for possibly seeing precipitation this coming week will
generally be for locations north of I-40, SW Virginia, and along the
southern Appalachians. The southern valley and plateau for example,
may escape unscathed this coming week with dry conditions, warmer
temperatures, and more sunshine than the aforementioned regions.

Based on our climate sites, Tri-Cities may be the only one that
struggles to reach climatological norms for the week under possible
impacts from the tropical system. Chattanooga and Knoxville on the
other hand, appear will mostly remain untouched this week with
temperatures creeping above climatological norms. Highs there will
range from the mid 80s, upper 80s, and close to 90 even. Humid
conditions will also trend upward towards the end of the week.

&&

.AVIATION...
(12Z TAFS)
Issued at 728 AM EDT Sun Sep 15 2024

VFR conditions will prevail through the period. Still expect some
gusts of 18-20kt at KTYS and KCHA today but the most recent runs
have backed off the duration of those gusts. Adjusted that
accordingly in the TAFs. Otherwise, light winds of less than 10kt
expected at all sites overnight.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             87  64  86  61 /  10  10  10  10
Knoxville McGhee Tyson Airport, TN  88  62  84  58 /  10   0  10  20
Oak Ridge, TN                       87  64  84  58 /  10   0  10  10
Tri Cities Airport, TN              82  59  79  58 /   0   0  20  30

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

SHORT TERM...CD
LONG TERM....KS
AVIATION...CD