Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tucson Arizona
900 am MST Tuesday Oct 13 2015
Synopsis...expect late Summer-like high temperatures through
midweek with record or near record highs on Wednesday. A pair of
low pressure systems will then bring a chance of showers and
thunderstorms with a cooling trend Thursday into this weekend.
Discussion...no surprises on the morning sounding. Plenty of
moisture still hanging around...but a stable atmosphere under high
pressure building overhead. An early look at the NAM and namdng25
show both the near record heat Wednesday and a solid chance of
showers and thunderstorms as early as Thursday afternoon. This is
reflected well in the current forecast. Please see the previous
discussion below for additional details.
Aviation...valid through 14/16z.
VFR conditions at all terminals with few-scattered clouds at or above 15k feet above ground level.
Expect winds to be mainly terrain driven at less than 10 kts.
Aviation discussion not updated for taf amendments.
Fire weather...dry conditions and unseasonably warm daytime high
temperatures will occur through Wednesday. 20-feet winds will be light
and terrain driven...with a general north to northwest component
developing for most areas this afternoon. Low pressure nearing the
area will then bring moisture and a chance for showers and
thunderstorms Thursday through the upcoming weekend. This pattern
change will be accompanied by a cooling trend and winds generally
out of the south to southeast at around 5-15 miles per hour.
Climate...here is a table of forecast temperatures and record temperatures for
Tucson International Airport 97 98/1991
Bisbee-Douglas Airport 92 94/2011
Ajo 100 101/1999
Fort Thomas 94 92/1965
Kitt Peak 83 83/1978
Organ pipe cactus 100 102/1995
Picacho Peak 98 100/1995
Safford ag station 95 98/1998
Sierra Vista fd 89 93/2011
Tombstone 91 93/1998
Willcox 92 93/2011
Previous discussion...dirty ridge amplifying overhead with patches of
middle and high cloud at times. Unseasonably strong height and
thicknesses will bring warmer temperatures today...and near
record heat Wednesday.
Our low is currently still cut-off from higher latitude influences
off the northern Baja California coast. It will meander up the western flank of
the newly amplified ridge position to a position off the Southern
California coast over the next 48 hours. Wednesday will see it
finally start to pick up higher latitude support once again...with
the feature finally shearing up the back side of the ridge just
ahead of a nice eastern Pacific trough. This will re-introduce a
chance of showers to the area Thursday into Friday while also taking
the edge off of the daytime temperatures.
As the trough pushes inland Friday...a stronger shot of energy
rounding into the bottom of the trough will increase our chance of
showers over the weekend. As the low lifts into the new trough
position northeast of the area early next week...temperatures will
have settled back into near or below average for middle October.
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