Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 241743

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
143 PM EDT Mon Apr 24 2017

A deep and vigorous low pressure system will slowly move from
the South Carolina coast to near Cape Hatteras by late Tuesday.
Expect drier and warmer weather Tuesday and Wednesday.  A
dissipating cold front crosses our region Thursday and Friday.


As of 1000 EDT: Widespread warm conveyer belt showers
continued, especially along and east of the Blue Ridge. With the
low level circulation progged to wobble progressively ENE along
the coastal plain today, strongest wcb forcing will refocus
acrs western and central NC.

Based on the QPF and lack of additional routed water, will remove
the Smokies and Little Tenn Valley areas from the flood watch and
leave everything else as is for now.


As of 300 AM EDT Monday: the upper low should be centered near
Myrtle Beach around 12z Tuesday, then wobble toward the northeast
along the Mid-Atlantic coast thru the Short Term. The associated
surface low will be stacked underneath, so the CWFA should see
gradual drying from west to east as the low drifts away. It may take
the entire day Tuesday for showers and clouds to clear along the
I-77 corridor, while the Upper Savannah Valley should see clearing
by early afternoon. So a decent temp gradient from mid 60s east of
I-77 to upper 70s in the Upper Savannah Valley can be expected.
Additional QPF on Tuesday should be light, as heavy rain will be
well east of the area.

From Tuesday night thru Thursday morning, conditions should be
quiet, as upper ridge quickly builds in behind the departing low.
Wednesday should be a nice day with mostly sunny skies and temps
back above normal. Highs in the 70s to lower 80s and lows in the 50s
to around 60.


As of 315 AM EDT Monday: A broad, massive trough will dominate the
CONUS in the upper levels to start the medium range, then will
retrograde west and allow a large ridge to build in across the
eastern states by the start of the weekend. A dying front will try
to reach the CWFA from the west on Thursday, and may bring enough
moisture to support a few showers and tstms in the mountains, but
otherwise, Thursday looks dry. Friday thru Sunday, the amplifying
ridge aloft should keep PoPs below climo, but a strong Bermuda High
in place will probably result in decent instability each afternoon
to support at least a few showers and storms, mainly in the
mountains. Highs will be about 10 degrees above normal, and lows
10-15 degrees above normal.


At KCLT: Flight restrictions could briefly/occasionally bounce
upward this afternoon in conjunction with gusty nely winds. Shower
activity should also remain light until more robust activity
overspreads the southern NC piedmont at some point after 20z. The
pattern remains favorable for renewed showers this evening into some
part of the overnight hours as winds gradually back to north and IFR
cigs lock in through daybreak.  Improving flight conditions are on
tap Tuesday, especially heading into the afternoon.

Elsewhere: Similar conditions to KCLT except generally better
conditions at KAND and KAVL. Winds will not be as gusty at KAVL as

Outlook: An area of low pressure will move slowly up the Carolina
Coast on Tuesday. Conditions should gradually improve later Tuesday
through Wednesday morning as dry air works in behind the departing
low. Return flow moisture ahead of the next system will develop late
in the week.

Confidence Table...

            17-23Z        23-05Z        05-11Z        11-12Z
KCLT       Med   64%     Low   44%     Med   78%     High  81%
KGSP       Med   64%     High  83%     Low   50%     Med   71%
KAVL       Med   64%     High  94%     Med   72%     Med   60%
KHKY       Med   78%     Med   67%     High  83%     High  81%
KGMU       Med   64%     High  83%     Med   72%     High  87%
KAND       High 100%     High 100%     High  89%     Med   65%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:


NC...Flood Watch until 8 PM EDT this evening for NCZ033-035>037-
SC...Flood Watch until 8 PM EDT this evening for SCZ001>014-019.


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