Rainfall – October 30/31, 2015 (Closed)

Heavy rainfall spread across portions of central Oklahoma on the 30th, with light precipitation continuing to fall into the early morning hours of the 31st.  The heaviest rainfall occurred near the Oklahoma City area, with lessening amounts the farther north and west from the metro you got.  A few places saw more than 2 inches of rain.

Outlook (Thursday-Sunday)

…Mild through the weekend / Heavy rain possible in the state on Friday…

A deep trough is located over the central part of the country this Wednesday afternoon.  An embedded short wave which was responsible for overnight light rain across the state, is approaching the Lower Mississippi Valley.  A strong mid-level jet max is digging southeastward across the Northern Plains.  These features will continue to march eastward over the next 24 hours.

Another strong segment of the mid-level jet stream is punching southward along the west coast.  This will carve out a deep trough over the Southwest and Rockies through Friday morning.  The trough will remain positively tilted and open as it moves across the Plains by early Saturday.  Heights will be rising slightly across the Southern Plains on Sunday, in advance of the next strong upper storm which will be approaching northern California and the Pacific Northwest.

Another weak cold front will be pushing south across the state by early Thursday.  North winds behind this front will veer to the east and southeast during the day as pressure falls occur across the Southern High Plains and Southern Rockies in advance of the strong upper trough.  A surface low will eventually organize near the Texas/New Mexico border on Friday afternoon.  This low will track eastward early Saturday, dragging a cold front across the state.  By Sunday, warmer air will move back into the state as winds become light out of the southwest.

There will be one chance of significant precipitation between now and the end of the weekend.  Models are in excellent agreement regarding the depth and quality of returning low level moisture, and lifting generating precipitation.  Showers will begin developing across southwest Oklahoma after Midnight early on Friday.  This precipitation will then increase in coverage and intensity as it spreads northeastward during the day.  By sunset, the heaviest precipitation will be located over the southeast part of the state, but light showers may persist in central Oklahoma until after Midnight early on Saturday.  Model guidance has been hitting on a signal of enhanced rainfall with amounts of 2 to 4 inches possible, but the location and amounts have varied slightly from run to run and model to model.  Currently it appears the most likely position for the heaviest rain will be near and just southeast of the I-44 corridor.

…Hazards…

Localized areas of flooding will be possible on Friday and early Saturday where the heaviest rainfall occurs.

…Okarche Weather…
Thursday morning (Midnight to Noon): Mostly cloudy.
Low: 42 Observed: 44
Chance of precipitation: 0.01 – 0%
Chance of precipitation: 0.10 – 0%
Chance of precipitation: 0.50 – 0%
Chance of precipitation: 1.00 – 0%
Observed: 0.00
Winds: Light.  Becoming northeast 5 to 15 mph.

Thursday (Noon to Midnight): Partly cloudy.
High: 64 Observed: 62
Chance of precipitation: 0.01 – 0%
Chance of precipitation: 0.10 – 0%
Chance of precipitation: 0.50 – 0%
Chance of precipitation: 1.00 – 0%
Observed: 0.00
Winds: East 5 to 15 mph.

Friday morning (Midnight to Noon): Cloudy. Showers and thunderstorms.
Low: 47  Observed: 44
Chance of precipitation: 0.01 – 100%
Chance of precipitation: 0.10 – 90%
Chance of precipitation: 0.50 – 20%
Chance of precipitation: 1.00 – 2%
Observed: 0.37
Winds: Southeast 5 mph.  Becoming southeast 10 to 20 mph.

Friday (Noon to Midnight): Cloudy. Showers and thunderstorms.
High: 53 Observed: 53
Chance of precipitation: 0.01 – 100%
Chance of precipitation: 0.10 – 100%
Chance of precipitation: 0.50 – 90%
Chance of precipitation: 1.00 – 20%
Observed: 0.73
Winds: Southeast 10 to 20 mph.

Saturday morning (Midnight to Noon): Mostly cloudy. Showers possible.
Low: 52 Observed: 48
Chance of precipitation: 0.01 – 30%
Chance of precipitation: 0.10 - 20%
Chance of precipitation: 0.50 – 0%
Chance of precipitation: 1.00 – 0%
Observed: 0.01
Winds: South 5 to 10 mph.  Becoming north 10 to 20 mph.

Saturday (Noon to Midnight): Clearing.
High: 66 Observed: 64
Chance of precipitation: 0.01 – 0%
Chance of precipitation: 0.10 – 0%
Chance of precipitation: 0.50 – 0%
Chance of precipitation: 1.00 – 0%
Observed: 0.00
Winds: North 5 to 15 mph.

Sunday morning (Midnight to Noon): Clear.
Low: 44 Observed: 42
Chance of precipitation: 0.01 – 0%
Chance of precipitation: 0.10 – 0%
Chance of precipitation: 0.50 – 0%
Chance of precipitation: 1.00 – 0%
Observed: 0.00
Winds: Northwest 5 to 10 mph.

Sunday (Noon to Midnight): Sunny.
High: 73 Observed: 72
Chance of precipitation: 0.01 – 0%
Chance of precipitation: 0.10 – 0%
Chance of precipitation: 0.50 – 0%
Chance of precipitation: 1.00 – 0%
Observed: 0.00
Winds: Light.

Late first freeze?

We have seen the low temperature in Okarche drop into the 30′s over the last couple of mornings, but we still await the first freeze of the season.  The chart above shows the percentage of previous years which had seen their first freeze by a certain date.  On this October 26, 33 percent of past years had already seen the first freeze.  The period of record goes back to 1936.

We will see this number hit 50% in a few days as we approach our average date of first freeze – October 30.  It does not appear as if we will see a first freeze by the average date.  In fact, medium range models show little chance of a freeze through November 11th, which would be very unusual.  By that date, 85 percent of previous years saw their first freeze.