Area forecast discussion
National Weather Service Jackson MS
1056 am CDT Friday may 24 2013
Update...
The forecast is generally on track with the only significant
adjustment made to extend slight chance probability of precipitation further in time this
afternoon. Latest analysis shows the northwest-southeast oriented surface cold
front pushing southwest into central and southeast Louisiana. A
distinct moisture/instability axis with ml cape > 2000 j/kg and
precipitation water >1.5 inches has set up along the front...and latest
guidance indicates it may support isolated shower/thunderstorm development
over the Natchez area for a little longer than earlier thought.
Otherwise...drier air will continue to advect in from the northeast
as evident in water vapor loop resulting in less humid conditions.
The updated aviation discussion is below. /Ec/
&&
Previous discussion... /issued 240 am CDT Friday may 24 2013/
Short term...today through Saturday night...
For today and tonight...the front will push south of the region and
be over the Gulf by this afternoon as strong Canadian high pressure
builds into the region from the north. Before the frontal passage in
the south there will be a slim chance of isolated convection in the
southwest until the frontal passage along with some patchy fog. The
National WRF models showed some isolated convection in the
southwest. The Storm Prediction Center WRF looked a little too aggressive with strong
storms in the southwest spreading north prior to dawn. After the
frontal passage high pressure will provide good drying in the low to
middle levels(pwats from 0.4 east to around 1 inch west) with some high
clouds coming into the region from northwest flow. As for temperatures highs
will be around normal with readings from the upper 70s north to the
middle 80s south. Lows will well below normal with readings from the
middle 40s east to the middle 50s west. This bring the risk of
breaking some record lows in the east for early Saturday. On climate
stats Hattiesburg record low of 52 in 1983 and meridians low of 47 in
1979. For temperatures went close to mav guidance.
For Saturday and Saturday night... during the period the upper ridge
axis over the plains will move toward the region. The front to the south
will come back over the region as a warm front during the period. A
weak shortwave will push into the region on Saturday night according
to GFS. Model cross sections shows dry air in the low to middle
levels...while the upper level will continue to bring high clouds
from the northwest. The NAM model keeps the shortwave west of the
region for Saturday night. Both models keeps the precipitation west of the
region. Highs on Saturday will be from the lower to middle 80s. Lows
will continue to below normal with readings from the lower 50s east
to the around 60 west./17/
Long term...Sunday through Thursday...building middle level heights
and southerly low level flow will develop and persist through the
early to middle parts of next week. This will lead to highs
generally in the middle to upper 80s with gradually increasing
humidity. The lack of instability and deep moisture combined with
the high heights should keep conditions dry through the period.
SW
&&
Aviation...
VFR weather with little in the way of aviation impacts expected next
24-36 hours. A band of high SC running from southeast Arkansas to near khbg is
fairly well depicted in 12z NAM 925-850 mb moisture forecasts. This
band is prognosticated to drift S and dissipate next 12 hours as high
pressure and drier air builds into area. North-NE winds may occasionally
gust to 20 knots at time during peak mixing thie afternoon. Combination
of winds staying up and drier low level air should preclude any fog
development overnight tonight...with only clouds being some
occasionaly passing high clouds associated with convectie debris from
upstream complexes. /Aeg/
&&
Preliminary point temps/pops...
Jackson 86 51 85 55 / 6 4 3 8
Meridian 87 44 85 50 / 4 4 3 6
Vicksburg 82 53 85 54 / 7 4 3 12
Hattiesburg 88 53 87 53 / 9 5 3 4
Natchez 84 56 85 59 / 20 8 7 10
Greenville 79 55 82 59 / 5 4 4 10
Greenwood 79 49 82 54 / 5 4 4 8
&&
Jan watches/warnings/advisories...
MS...none.
La...none.
Arkansas...none.
&&
$$
