Area Forecast Discussion
Issued by NWS Tulsa, OK

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258
FXUS64 KTSA 180856
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
256 AM CST Wed Jan 18 2017

.DISCUSSION...

The main items to discuss in this morning`s forecast are: 1)
Rain/thunder chances today and tomorrow, and 2) Rain/thunder
chances this upcoming weekend in what will become an active
weather pattern over the CONUS, and finally 3) The big change in
temps this week compared to late last week and weekend.

An elongated upper level low pressure, extending from SW KS
southwest to NW Mexico, has two embedded PV maxes, one on each end
of the broader circulation. The lead system currently lifting
toward the central High Plains, induced warm/moist advection on
the cool side of a stalled front down near the Gulf Coast. Will
continue chance pops in the far E and S as this next batch of
showers lifts northeast from Texas. Instability this far north of
the front looks to low to include thunder mention during the day.
Another round of showers is expected to organize over the ArkLaTex
by late today and into the evening, in association with the
approach of the southern PV max. This activity may graze far
eastern OK and western AR. Instability increases some by this
evening, so an isolated thunder mention was added. The main upper
low will lift out of the southwest and into the Plains by
Thursday. As the parent upper trough axis swings across the region
Thursday afternoon/evening, there is some indication from both the
GFS and ECMWF that a few afternoon storms could form in the steep
lapse rate environment beneath the -20C 500mb temps. This activity
should taper off during the evening as the low becomes an open
wave and lifts NE away from the region.

Very strong upper jet energy over the Pacific has already begun to
impact the US West Coast. This upper jet energy will propagate
downstream across the southern tier of states going into the
weekend. A pair of smaller scale PV maxes on the nose of this
upper jet will move into the Plains Friday and again late Saturday
into Sunday. The initial system Friday will take a sharp
northeastwardturn and will stay well N and W of the better
moisture, so very little impact is expected from this one. The
second system will take a more southern track and will be able to
tap the better moisture. A band of rain and embedded storms mainly
on the north side of a developing 500mb circulation will affect
the area Saturday night into Sunday, with the rain tapering off
quickly from W to E Sunday night as the system continues east. The
very southern track of the jet stream suggests that the true warm
sector will not make it into our area thru the period. Thus, as it
looks right now, severe potential will be pretty low.

The trend toward a much more progressive pattern over the CONUS
will not be favorable for arctic intrusions. Temperatures will run
above average overall, and sometimes much above average, thru
this forecast. The latest ECMWF does suggest that some bucking of
the jet will occur, and a higher amplified positive PNA pattern
will evolve in week 2. A positive PNA pattern is generally quiet
for our area.

Lacy

&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   54  44  61  45 /  10  10  10  10
FSM   52  46  61  47 /  40  30  20  20
MLC   53  46  63  47 /  20  10  10  10
BVO   54  42  59  42 /  10  10  10  10
FYV   52  44  59  45 /  30  30  20  20
BYV   49  43  56  44 /  20  30  30  20
MKO   54  45  62  46 /  10  10  10  10
MIO   52  44  60  44 /  10  20  20  20
F10   53  44  62  46 /  10  10  10  10
HHW   53  48  65  48 /  40  20  10  10

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&

$$

LONG TERM....30



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