Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Jackson MS
349 am CDT Thursday Jul 10 2014
Short term...today through Friday night...
latest satellite imagery showed an upper trough over the Mississippi
Valley with some weak upper divergence. A weak shortwave on the base
of the trough was bringing in some convection across the region. The
weak surface frontal boundary currently located to the north of the
area will drop south into the area this afternoon. Precipitable waters around 2
inches will decrease from the north as the weak front moves into the
region. Precipitable waters will decrease to around 1-1.3 inches behind the
boundary. A dry slot of less than one inch will move into the region
Friday night. With little upper support expect the weak surface
frontal boundary to stall across area by this evening. So will keep
chances of convection going through this evening until after sunset.
With marginal instability and weak shear under decent cloud cover
expect these storms to remain sub-severe...but a strong storm or two
look possible this afternoon and early evening with daytime heating.
There also could be some locally heavy downpours with some limited
flooding potential with the light corfidi vectors. With lack of upper
support the activity should diminish this evening. On Friday the
upper trough will lift east of the region as upper ridging builds in
from the west. This will push the surface boundary away from the
region. On Friday expect diurnal convection to be around with
isolated coverage across the south during the afternoon which will
diminishing by evening. We should get better insolation for warmer
temperatures on Friday.
As far as temperatures are concern went closer to NAM guidance for today highs
in the middle to upper 80s due to cloud cover. For Friday went closer
to the warmer gmos guidance in the middle 90s. For nightly lows went
closer to the milder blend of NAM/mav guidance with lows in the middle 60s
to around 70. As far as probability of precipitation made some adjustments to MOS probability of precipitation with
better coverage for today. Went close to MOS probability of precipitation for tonight and
Long term...Saturday through Thursday...the first half of the
extended will be fairly quiet as upper ridging will be in place
overhead. This will lead to mostly dry conditions and warm
temperatures. There could be some chance for an isolated storm in
the south through the weekend as daytime heating will combine with
enough instability and moisture in place. The GFS showed some drier
precipitable water values coming through the region which would preclude
showers/storms from developing. The NAM and European model (ecmwf) on the other hand
continue to show precipitable water values around 1.5 to near 2 inches through the
weekend. This...along with highs reaching into the middle 90s...could
spark some convection and leaned closer to the NAM/ECMWF.
Heading into the week...the upper ridging gives way to a rather
large upper trough that will be located across the Great Lakes
region. This will take up residence through the rest of the period.
A series of waves will move through the base of the trough...one of
which will send a cold front in our direction. This front will move
into the arklamiss Tuesday into Wednesday. Both the GFS and the
European model (ecmwf) bring the front all the way through the County Warning Area by early Thursday.
Given plenty of moisture ahead of the front...we will see a better
chance for showers and storms come Tuesday and Wednesday. Behind the
front. Also behind the front...some cooler air will be possible with
some below normal temperatures possible. /28/
Aviation...a frontal boundary pushing south across the area will
bring additional rain showers/thunderstorms and rain activity for today until around 01z.
Outside of convection...MVFR category fog and a few patchy areas of
low stratus will be common during the early morning hours.
Otherwise...VFR conditions will prevail outside of storms./17/
Preliminary point temps/pops...
Jackson 88 68 95 68 / 45 14 5 9
Meridian 88 67 95 65 / 49 13 5 9
Vicksburg 87 66 96 66 / 50 14 7 8
Hattiesburg 86 70 96 70 / 59 21 19 7
Natchez 86 69 95 70 / 60 18 17 6
Greenville 89 69 96 70 / 30 5 2 8
Greenwood 89 67 94 66 / 27 5 2 9