Scientific Forecaster Discussion
fxus64 koun 281711
Area forecast discussion
National Weather Service Norman OK
1211 PM CDT sun may 28 2017
VFR conditions to continue. This afternoon will see decreasing
north winds and some cu across the area. Winds become light
overnight with clear skies.
Previous discussion... /issued 508 am CDT sun may 28 2017/
.12z aviation discussion...
Aviation... /for the 12z tafs/
short term model guidance shows low levels are fairly moist this
morning, but not saturated. Considering this, and latest
observations from across the region all being VFR, we're fairly
confidence that VFR conditions will occur through the taf period.
Northerly winds may become variable for a period this evening
before becoming southwesterly and remaining light tonight.
Previous discussion... /issued 329 am CDT sun may 28 2017/
fairly strong westerlies aloft were present tonight between
mean ridging to our south and Canadian closed low centered near
Lake Winnipeg. Mid-level flow transported deeply mixed air from
the Mexican plateau region eastward earlier across the Southern
Plains atop a very moist boundary layer resulting in very high to
extreme instability. Convection initiated first along the dryline
and then along a southward moving cold front. As of this writing,
deep convection and heavy rain/severe threat has shifted south of
the area. We have a couple of remaining flash flood warnings due
to runoff from earlier heavy rainfall. We also have a Flood Watch
that we will be able to cancel shortly.
Few changes were needed to the forecast. Cooler temperatures
(around normal for late may) are expected today, along with
drier/less humid air mass. Aloft, mid-level heights will generally
slowly build through early next week limiting our chances for
precipitation. A shortwave trough within northwesterly flow may
result in some convection late Tuesday, as deeper moisture and at
least modest instability return. Better chances will exist on
Wednesday through the end of the forecast period as a weak closed
low moves toward the area from the west and moisture/instability
continue to increase. By this time medium range guidance
uncertainties grow, and this leads to uncertainty as to when the
highest probabilities will occur. For now we were fairly broad
brush with chance probabilities each day and over the next few
days we will be able to better refine periods of greater chances.
Temperatures should be near or just above normal through the
period with not significant variations from day to day.
Preliminary point temps/pops...
Oklahoma City OK 82 58 87 60 / 0 0 0 0
Hobart OK 82 57 87 59 / 0 0 0 0
Wichita Falls Texas 83 59 87 61 / 0 0 0 0
gage OK 79 53 85 57 / 0 0 10 10
Ponca City OK 81 56 85 59 / 0 0 0 10
Durant OK 82 61 86 62 / 20 10 0 0