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Area forecast discussion
National Weather Service Birmingham Alabama
643 PM CDT Thu Apr 26 2018

Update...
aviation discussion.

&&

Short term...
through tonight.

The 500mb upper low center was located near Tupelo, MS, this
afternoon and will track across north Alabama this evening. The
primary band of stronger forcing has pushed into Georgia and a mid
level dry slot has wrapped into south central Alabama ahead of
the upper low. Very cold temperatures (-22c) associated with the
upper low center has produced limited instability across north
Alabama. A few thunderstorms have developed to the east of the
upper low center, producing small hail. There is still a small
window of opportunity for stronger storms to develop during the
heating of the afternoon, but severe potential is very small at
this time.

Even though the upper low will quickly track off to the east tonight,
a wide swath of clouds around the upper low will result in mostly
cloudy skies overnight. Scattered showers will continue through
the early evening hours for areas near and to the east of the
upper low, but expect most of the rain showers to dissipate by 9
or 10 PM.

58/rose



Long term...
Friday through Thursday.

A deep trough remains in place over the eastern Continental U.S. This weekend.
Another shortwave moves through the trough on Friday and could be a
focus for some extra lift in central al; however, moisture return is
expected to be minimal behind the departing cold front. Therefore, I
don't expect much rain coverage for our area through the weekend.

A surface high pressure slide southeastward through the upper
Midwest and into the southeastern US Sunday into Monday. Upper level
ridging also builds in across region at this same time. Expect a
slight warming trend for the beginning of next week with rain-free
conditions.

A shortwave trough digs into the Pacific northwest and continues
southeastward into The Four Corners region Tuesday into Wednesday.
This will push the surface high pressure eastward, placing it over
the coastal mid-Atlantic region during the day on Wednesday. This
Marks a return of the southerly flow for central Alabama as we're caught
between a trough to our west and ridging to our east. The GFS tries
to bring in some moisture, and with the help of some isentropic
lift, develops some brief showers Wednesday afternoon. The European model (ecmwf)
keeps any light precip remaining off to our west, so will keep any
pops on the lower end given we're still 7 days out on that.

Overall, expect a more Spring-like weekend and week ahead with mild
overnight low temperatures and warm afternoon highs.

25/Owen

&&

Aviation...
00z taf discussion.

The upper low is currently over southeast Tennessee and will continue to
move further from central Alabama tonight. In its wake, lingering
showers will quickly diminish this evening. Low clouds however will
remain across the area for much of the forecast period. For most
locations, current cig heights are VFR. Expect those heights to
decrease through the evening, with MVFR to IFR cigs overnight.
Clouds will lift Friday morning, with skies becoming scattered by 15-
17z.

Westerly winds will diminish this evening, remaining at 3-5kts
overnight and turning to the northwest. Northwest winds prevail
through the day tomorrow, increasing to 8kts during the day.

14



&&

Fire weather...

A cold front moving through today will bring wetting rains to all
of the area. Drier conditions move in after tonight. Afternoon
minimum relative humidity values will drop to upper 30s through
the weekend. There are no fire weather concerns at this time.

&&

Preliminary point temps/pops...
Gadsden 48 71 47 74 45 / 40 0 0 0 0
Anniston 50 73 48 75 46 / 30 0 0 0 0
Birmingham 49 73 51 76 49 / 10 0 0 0 0
Tuscaloosa 51 73 51 76 49 / 10 10 0 0 0
Calera 50 72 50 75 49 / 10 0 0 0 0
Auburn 51 72 51 74 50 / 20 0 0 0 0
Montgomery 52 74 51 77 51 / 10 0 0 0 0
Troy 52 73 52 77 51 / 0 0 0 0 0

&&

Bmx watches/warnings/advisories/...
none.

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