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Area forecast discussion...update 
National Weather Service Jackson MS
834 PM CDT Thursday Oct 23 2014

Update...upper level disturbance passing across the region this
evening at the back end of evolving northwest flow regime over the
eastern Continental U.S. Will provide US little impact despite some passing
overnight clouds. Clouds helped keep temperatures cools this afternoon and
a window of mostly clear skies later tonight at most spots will
allow for decent radiational cooling and temperatures well down in the 40s.
Winds will probably not go calm enough to allow for optimal
radiational cooling and/or patchy ground fog. Updates to the
previous forecast were minor. /Bb/

&&

Previous discussion... /issued 246 PM CDT Thursday Oct 23 2014/

Discussion...
short term (tonight through saturday)...dry conditions will continue
through the short term period with gradually moderating
temperatures.

High level clouds continue to stream across the area as an upper
trough swings through the region overnight. Radar has been detecting
some echoes around 10 kft and higher. Given the dearth of moisture in
the low and middle levels...it is unlikely that measurable rain will
occur as this precipitation struggles to make it to the surface.
Nevertheless...clouds will be thick enough in some areas to
interrupt viewing of the partial solar eclipse.

Heading into the weekend upper ridging will build eastward into the
area with high pressure building in at the surface. In spite of
continued light northerly...and then westerly...surface flow
temperatures will moderate with highs returning to above normal by
Saturday. /Dl/

Long term (sunday through next friday)...at the beginning of the
period...middle level pattern will be dominated by a longwave ridge
extending from Texas northward through the eastern plains and into
Canada. Dry northwest flow continues over the County Warning Area. Meanwhile...a pattern
changing system will be digging into the Pacific northwest and then rapidly pull
into the intermountain west by Sunday afternoon.

The system continue to deepen as it pulls into the western High
Plains while its attendant cold front approaches the middle MS Valley.
Down in our neck of the Woods...surface high pressure will slide
east as middle level SW flow gets underway Monday. This warm air
advection regime will slowly begin increasing moisture...but it will
take some time given the dry air in place (pw/S < 0.75 in).

GFS/European model (ecmwf) indicate that moisture availability will be sufficient
enough (pw/S 1-1.5 in) by Tuesday to combine with the good
isentropic lift for showers to break out by the afternoon.
Instability looks pretty meager...thus just expecting showers
initially.

Moving into Wednesday...European model (ecmwf) looks slightly deeper and more
progressive with the system as it pulls into the MS/Ohio valleys.
Boundary looks to be slowing in the GFS as it becomes oriented
parallel to the middle level SW flow. While differences exist in the
GFS/European model (ecmwf) on the evolution of the frontal boundary at the end of the
period...it seems prudent to continue rain chances as pattern
suggests that isentropic ascent will continue overtop of the
boundary. Lapse rates still look scanty so will continue with just
showers for now. /26/

&&

Aviation...middle and high clouds associated with an upper level
disturbance will continue to move over the forecast area through
this evening until the disturbance shifts east. Otherwise....VFR
conditions will prevail at all sites through Friday night. Northerly
winds this afternoon of 3-6 knots and will subside to near calm this
evening...and remain so overnight into Friday morning. /22/

&&

Preliminary point temps/pops...
Jackson 45 75 49 82 / 1 0 0 0
Meridian 42 76 42 80 / 0 0 0 0
Vicksburg 41 77 45 83 / 2 0 0 0
Hattiesburg 44 77 45 81 / 0 0 0 0
Natchez 44 74 49 80 / 1 0 0 0
Greenville 45 75 51 84 / 3 0 0 0
Greenwood 43 75 48 82 / 2 0 0 0

&&

Jan watches/warnings/advisories...
MS...none.
La...none.
Arkansas...none.
&&

$$

Bb/dl/26

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