Area Forecast Discussion
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FXUS64 KMRX 240805
Area Forecast Discussion
National Weather Service Morristown TN
405 AM EDT Mon Oct 24 2016
.SHORT TERM (Today and Tonight)...
Surface high pressure continues to dominate the short term forecast
with clear skies, unseasonably warm daytime highs, seasonably cool
overnight lows and low relative humidities. Passage of a backdoor
cold front by this evening will bring northerly surface winds and
reinforce the dry low-levels. Aloft, ridge of high pressure
continues to contribute to the dry deep layer northwesterly flow
with PWs across the area stuck in the 0.3-0.6 inch range.
Model soundings consistently show a very dry layer at around
800-850 MB with dew point depressions on the order of 20-35 area
wide. Bottom line...this dry air mass will allow afternoon RH
values to dip into the low 30`s across much of the East Tennessee
Valley. The result is a continued marginal fire weather risk across
the area during this prolonged period of drought.
.LONG TERM (Tuesday through Sunday)...
No change in mild mostly clear pattern Tuesday and Wednesday with
Upper level ridge centered over the south central states. Northwest
flow aloft and dry air mass to continue. Highs in the 70s lower
elevations and 60s higher elevations. A cool night again Tuesday
night with lows upper 30s NE to lower 50s SW. Surface low develops
over Iowa Wednesday then moves into the Ohio Valley Wednesday
night. South to Southwest flow will increase Wednesday night as
clouds increase ahead of this system. Showers move in late
Wednesday night and Thursday morning across east Tennessee as cold
front approaches. Models still keep most of the energy with this
system over the Ohio Valley and Great Lakes so only brief period of
showers across east Tennessee. Some instability present but thunder
threat Thursday still looks low. Rain will move out Thursday night
with skies clearing and high pressure building back in Friday. A
new low pressure area moving southeast across Great Lakes late
Friday and Friday night...then the Ohio Valley on Saturday should
get close enough to spread clouds and a chance of rain to northern
sections of the area Saturday and northeast sections Saturday
night. Temperatures to remain above normal through the extended.
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 80 49 77 49 / 0 0 0 0
Knoxville McGhee Tyson Airport, TN 76 44 73 45 / 0 0 0 0
Oak Ridge, TN 76 45 74 45 / 0 0 0 0
Tri Cities Airport, TN 72 38 69 38 / 0 0 0 0