Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Jackson MS
353 am CDT Friday Jul 31 2015
Short term...the main story in the short term will be the drier air
and lower relative humidity values. While less humidity will be welcome...this may
have an impact on fire weather conditions (more on that below).
Drier air continues to filter into the County Warning Area this morning with the surface
boundary on the southern fringes of the area as of 3am. Surface dewpoints
in the middle/lower 60s exist and are expected to reach the upper 50s
for some locations this afternoon. Surface temperatures will be lower than what
we have seen in recent days and highs are only expected to reach 91-
95 range. Deep layer dry air is also associated with this boundary
and precipitable waters will run 1.0 to 1.3 today and trend to 0.75 to 1.0 tonight
into Sat night. That is substantially dry for this time of year and
the result will be very little in the way of clouds into the
weekend. Overnight lows will be most affected from the dry air and
looks to yield middle/upper 60s for low temperatures the next two mornings.
Additionally...as we warm today...look for some gusty winds from the
north-northeast and likely peaking near 20-25 miles per hour.
With the drier air and lowish relative humidity values (30-40%)...the fire danger
will be on the increase. Combine that with the lack of precipitation over
the past 3 weeks...some burn bans in effect and increased winds
today...will introduce a limited threat to bring attention to this
risk and mention burning is discouraged. /Cme/
Long term...Sunday through Thursday...GFS/ECMWF in general
agreement at the beginning of the period with middle/upper level pattern
characterized by ridging in the western US and a general troffiness
over the northeast and east central portions of the nation. In the
lower level...light northerly winds look to maintain the dry air with
dewpoints remaining in the 60s.
Shifting surface high pressure will allow surface winds to become
more southerly by Monday and begin tapping into the higher dewpoints
just to the south of the County Warning Area. A few isolated storms look possible in
the afternoon as lower 70s dewpoints move back in. Tuesday will have
similar scenario with isolated storms in the south in the afternoon
and occurring a little further north than Monday.
By late Tuesday night into Wednesday morning...with dewpoints now in
the 70s overspreading the region...a series of shortwaves dropping
southeast in the northwest flow will kick off some isolated convection that will
become more scattered during maximum heating Wednesday afternoon and
into Wednesday night.
This convection will serve to moisten up the lower levels as
dewpoints look to be in the middle 70s for Thursday. This along with
expected highs in the 90s will combine well for airmass type
convection again for Thursday afternoon...especially in the east in
proximity to the departing shortwave./26/
Aviation...VFR conditions will prevail this taf period. The only
concerns will be gusty north-northeast winds today. Look for gusts to peak
between 18-25kts. /Cme/
Preliminary point temps/pops...
Jackson 93 68 94 68 / 0 0 0 0
Meridian 92 64 93 65 / 0 0 0 0
Vicksburg 93 66 94 65 / 0 0 0 0
Hattiesburg 95 69 95 69 / 8 5 4 4
Natchez 92 67 93 68 / 1 0 0 0
Greenville 92 67 94 68 / 0 0 0 0
Greenwood 92 66 93 66 / 0 0 0 0