Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Jackson MS
359 PM CDT Friday Aug 28 2015

Discussion...a more expansive cumulus field developed today generally
along and east of I-55 but vertical development was almost none and
any shower activity remained well east in central Alabama. Deep layer
moisture will increase very gradually through the weekend and into
early next week as rather light southerly/southeasterly low level flow sets up. Precipitable water
values just below an inch this afternoon will increase to around
1-1.2 this weekend. Isolated afternoon convection will be possible
mainly over eastern zones Saturday and Sunday as a weak middle/upper
trough/low swings from along the MS/Alabama border eastward. This feature
will be succeeded by a new upper trough extending from the Midwest
to the northwest Gulf Coast on Monday, which will likely aid in increasing
probability of precipitation somewhat by the middle of next week.

Ts Erika remains quite disorganized with an ill defined llc and is
now approaching Hispaniola. This lack of organization has allowed
the system to continue to avoid greater influence from upper level
steering and instead continue on a more westerly track. As a result,
the official track forecast now takes the system along the West Coast
of Florida, though it also shows weakening. As Erika passes over the
mountainous terrain of Hispaniola tonight, it is entirely possible
the storm could degenerate into a tropical wave. Regardless of how it
emerges into the eastern Gulf early next week, there is even more
uncertainty toward the end of the week. The 12z GFS shows a middle/upper
trough which would deflect any surface low to our east, but the 12z
ecm and ecm ens a weakening upper trough midweek. If anything, as
suggested by the previous shift, it is not out of the realm of
possibility for our area to receive rain from this system toward the
end of the week, but confidence is low.

Portions of the previous long term follow below... /dl/

Global models show a general consensus for a significant pattern
change over the Continental U.S. As we go into next week. An upper level trough
is forecast to set up over the west while a high amplitude ridge
surges well north into eastern Canada and encompasses most over the
central/eastern Continental U.S.. in the transition...a weak upper level trough over
the lower MS valley is forecast to cut off and meander around as the
primary belt of westerlies becomes displaced well to the north.

The net effect for the arklamiss should mean gradually increasing
moisture and warmth early next week...but convective development
should be slow to increase given the expectation for middle level
capping and little opportunity for lift. New guidance
temperatures/probability of precipitation are in line with the forecast trends from the past
few days and only made minor adjustments. /Ec/

&&

Aviation...VFR conditions will prevail for the remainder of today
and into Saturday morning. Winds will subside this evening...and
will remain light to calm overnight into Saturday morning. /19/

&&

Preliminary point temps/pops...
Jackson 68 91 68 92 / 0 8 8 9
Meridian 67 88 66 90 / 5 19 15 14
Vicksburg 62 92 65 92 / 0 4 4 8
Hattiesburg 67 89 68 91 / 3 13 13 12
Natchez 63 90 67 89 / 0 3 4 10
Greenville 64 92 68 92 / 0 4 5 10
Greenwood 66 90 67 91 / 0 8 9 13

&&

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

$$

Dl/19/ec

National Weather Service Glossary of Abbreviations