Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Jackson MS
529 am CDT Tuesday Jul 22 2014

Short term...the primary weather feature affecting the arklamiss
will be a closed cold core low migrating westward from Alabama into MS.
There is a weak surface reflection that will aid in low level
moisture convergence over eastern MS later this morning and
afternoon as deeper moisture surges westward toward the Interstate
55 corridor and combines with daytime heating. Hrrr guidance
indicates cape values peaking in the 2000-3000 j/kg range and
precipitable water approaching two inches - and this will support
thunderstorm initiation along the ll moisture convergence axis
stretching north of the low center. High-res model output varies in
coverage but there may be sufficient easterly middle level flow to
support multi-cell storm clusters along any boundaries with storms
capable of producing some strong wind gusts. The movement of storms
in this flow pattern would increase rainfall coverage and have
raised probability of precipitation some for today.

Expect convective activity to wane after sunset this evening. The
closed low will continue its westward migration overnight and better
moisture convergence should set up farther west Wednesday...and have
shifted probability of precipitation slightly in that direction - a little more than MOS
guidance suggests. The thermodynamic and wind profiles should be
similar Wednesday and a few strong storms would be a possibility
once again. It looks like northern stream shortwave energy
approaching the area late Wednesday night is a little slower in the
model guidance...and the greater influence on arklamiss weather may
hold off until Thursday. Have raised probability of precipitation above guidance to maintain
some continuity...especially with the possibility of convective cold
pools that could help to send shower/thunderstorm activity a little farther
south than expected into northern portions of the area. /Ec/

Long term...Thursday to Tuesday. So big pattern change for
the region. With the large area of high pressure planted over The
Rockies...the arklamiss will continue to get fronts and weak
disturbances every few days. The MOS continues to bounce around with
the temperatures. Perhaps leaning more toward climatology for this
time of year...the temperatures in the extended are back into the upper
90s/middle 70s early next week which would suggest possible increase in
heat stress. However...with the current pattern temperatures are
likely to be at or below normal through the extended. Stuck with
guidance generally for probability of precipitation and temperatures.

By looks like the latest stalled front will be
replaced with an approaching cold front. This boundary is likely to
stall along the coast over the weekend...before the next front moves
into the region around Monday. Each system seems to be lacking much
upper level support and the main surface low with each system is
also distant. However...the models are bringing in plenty of very
moist and unstable air from the Gulf. There is a chance of rain
across the area nearly every day. With the best dynamics associated
with the systems staying to the north and the western ridge wavering
further east some days...much of the thunderstorm activity will miss
the western zones...basically areas east of Interstate 55 through
the period. Of course there could be some isolated to scattered
thunderstorms...but probability of precipitation right now are low. Between each front will
be a day or two of mostly clear skies and mild conditions. Not
anticipating a pattern shift this forecast period.


Aviation...patchy areas of fog will mix out quickly after sunrise
this morning and VFR conditions are expected to prevail through
tonight. Increasingly moist and unstable air will support better
afternoon rain showers/thunderstorms and rain coverage...especially along and east of the
gwo/Jan/mcb corridor. /Ec/

Preliminary point temps/pops...
Jackson 90 71 91 71 / 34 32 34 22
Meridian 89 69 91 69 / 52 39 28 23
Vicksburg 90 70 92 71 / 20 20 34 22
Hattiesburg 90 70 92 71 / 41 25 26 21
Natchez 89 70 90 71 / 21 15 38 20
Greenville 92 72 93 73 / 15 12 24 27
Greenwood 91 71 91 72 / 25 21 29 27


Jan watches/warnings/advisories...



National Weather Service Glossary of Abbreviations