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000
FXUS61 KPBZ 161957
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
357 PM EDT Tue Apr 16 2024

.SYNOPSIS...
Low pressure over northeast Nebraska will move into southern
Minnesota tonight before crossing Wisconsin on Wednesday. An
associated warm front will lift across the Upper Ohio Valley
Wednesday with showers and thunderstorms resulting. A cold front
crosses Ohio late Wednesday with the threat of severe
thunderstorms. Dry weather will briefly return Thursday before
another cold front brings showers on Friday.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
KEY MESSAGES:

-  Dry weather to continue most of area as high pressure slides
  east.
-  Mild night with lows 15 to 20 degrees above normal.
------------------------------------------------------------------

500 mb ridge over Ohio should move into western Pennsylvania
after midnight. Dry airmass is in place currently but stalled
front over southern Ohio is moving back north. Satellite shows
ACCAS over central Ohio in this area of warm advection and
moisture return with surface Tds of 55-60F south of the front
headed north. Should be a mild night with increasing moisture
and cloud cover holding temperatures up in the lower 60s in the
far southern and western zones and about 15F above normal in
Pittsburgh metro.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:

- Slight risk for severe weather Wednesday afternoon and evening
  with damaging winds primary threat.
- Seasonably warm temperature to persist through Thursday.

-----------------------------------------------------------------

Approaching trough should result in 500 mb height falls on the
order of 70 meters during the day. Along with warm advection
regime showers and thunderstorms will be possible during the
morning and early afternoon with the first round. The first
distinct surge of 1000-500 mb moisture transport arrives around
15z with warm advection regime, with a secondary surge around
00z with the cold front.

Sufficient clearing behind morning convection in Ohio should
lead to destabilization with a band of thunderstorms forming
over northern Indiana and moving across northern and central
Ohio during the afternoon. Would expect these to impact Ohio
counties from 5-8 pm and Pennsylvania/West Virginia Counties
8-11 pm. HREF shows surface Tds in the lower 60s in western
Ohio, but more in the 55-60F range further east.

While Supercells with hail/tornadoes can`t be ruled out, the
CAMS suggest a fast moving line of storms with damaging winds
being the most likely threat. Given soggy soils and high river
flows, a flash flood threat exists with any storms despite that
fast motion.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
KEY MESSAGES:

- Brief dry period expected Thursday.
- Showers likely Friday with passage of a surface cold front.
- Pattern shift will lead to drier but cooler conditions
  Saturday through Monday
-------------------------------------------------------------------

500 mb heights rise 40 to 60 meters Thursday under short wave
ridging and a decent drying through column. However, strong
trough heading into the Great lakes Thursday night will bring
another cold front Friday. Showers are expected along this cold
front arriving very early Friday morning in Ohio and during the
morning elsewhere as Upper trough skims north of area but
provides lift and support for a wave of low pressure to race
through eastern Great Lakes.

Looking more and more like a four day period of dry weather
could be in store centered on the weekend.

Heights fall Friday night and Saturday more than 100 meters and
a decent amount of cold advection occurs ending the mild spell.
In fact, 850 mb temps are forecast by guidance to fall into -4
to -6C range by Sunday morning over the northern half of
forecast area. NBM 10th percentile MinT range from 28 to 32F
across the rural areas of the central and northern forecast
area Saturday night.

The lingering light winds under the surface high and dry
conditions suggest a cold radiation night Sunday night. NBM 10th
percentiles again suggest a hard freeze (28F) is possible in
the north and near freezing temperatures elsewhere. While mid to
upper 30s are the most likely low temperatures over the
weekend, some of the colder wind protected valley sites have the
potential to freeze either night. While it isn`t yet May, the
warm winter and spring has resulted in an early growing season
particularly from the Pittsburgh area on south.

A fast West to northwest flow regime with dry conditions should
continue into Monday before a more well defined short wave
trough crosses the Great Lakes Monday night and the Upper Ohio
River Valley Tuesday with showers possible.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
High pressure over the area maintains VFR conditions and light
winds through the remainder of the day today. An approaching low
pressure system and passing warm front will bring increasing
mid and high clouds and southerly winds, along with the
potential for rain showers Wednesday morning. At this time, hi-
res ensemble probabilities for MVFR ceilings remain low across
the area until later in the day Wednesday. In fact, even
probabilities for 5kft ceilings remains low (less than 30%)
until after 15Z when slightly higher probabilities (30-50%)
begin to creep in from the west and along the high terrain.


.Outlook...
VFR will prevail until restriction potential returns Wednesday
with approaching low pressure and associated showers and
thunderstorms. Restrictions remain possible Thursday and Friday
under a subsequent upper trough and continued chances for rain.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

$$

SYNOPSIS...Craven
NEAR TERM...Craven
SHORT TERM...Craven
LONG TERM...Craven
AVIATION...Cermak