Warmer Along with Gusty South Winds.

Let’s see, the high yesterday was only 57 which occurred shortly before midnight and that happens to be within 3 degrees of the coolest maximum temperature on record for that date.  Then, today the high has so far been 72 which is within a few degrees of normal for this time of year.  That will be followed by a high on Saturday well into the 80s and we are still expecting to threaten the records for Sunday and Monday when afternoon high temperatures will be near 90 as you can see on our forecast page.  Ah, the challenges of forecasting OK weather.  By the way, here is a graphic showing the expected temperature trends over the course of this forecast cycle.

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As mentioned in yesterday’s blog, the cool air had not penetrated completely through the state on Thursday so the warmer air was not too far away.  A return to southerly winds today have helped to bring the warmer air back this way and gusty southerly winds over the course of the weekend will really help warm things up.  Not only that, but the southerly winds will also bring those dew point temperatures back into the 60s so not only will it be very warm by October standards, it will also be very humid.  Minimum relative humidity values should be around the 50% level during the heat of the day.

For tonight, the southerly winds and return of warm, humid air means temperatures will not be dropping much and we expect to start the day well into the 60s.  Low level clouds are also expected to reform which will then be slowly burning off during the morning hours with skies becoming partly cloudy by afternoon.  Lots more sunshine will be the general rule through the day Sunday & Monday.  It will also be very windy with southerly winds holding near 15 or more through the overnight hours and 15-30 with some higher gusts during the daytime hours right on through Monday.

The next frontal boundary looks to arrive late Tuesday or that night with only a slight chance of showers for Wednesday.  That will be followed by a cool-down for the next few days, but another warm-up is expected by the following weekend.  However, the longer range guidance has not been very consistent regarding this time frame and will try to illustrate that with a series of charts showing the flow aloft at around the 18,000’ level or 500 mb.

These charts are generated by one of the extended range forecast models known as the GFS.  Here is its forecast that was initialized this past Wednesday morning and is valid for next Friday, the 21st of October.  Notice the ridge aloft located over the southern Rockies and the position of the jet stream.

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Next is the same level as initialized yesterday and the forecast again valid for this coming Friday, Oct 21.  Notice the ridge has amplified somewhat and the jet stream has repositioned somewhat as well.

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Then, there is the chart initialized this morning and also valid for the same time frame.  Quite a difference needless to say.  In fact, this solution would suggest a very wet period for the latter part of next week and it is this sort of discontinuity that can lead to substantial changes in forecast variables and also forecast uncertainty.

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Although not shown here, the same charts valid for the same time frame only using a different long range forecast system known as the ECMWF has been much more stable and therefore the forecast generated by the GFS for that time frame has been considered an outlier and discounted.  The forecast you see on our forecast page reflects what is considered to be a more likely outcome which is why we have a dry forecast for the latter part of next week as opposed to what would be a very wet forecast if only the GFS was relied on.

Keep in mind, this sort of discontinuity also contributes to additional uncertainty regarding those longer time ranges, but thought perhaps this illustration would help to explain why sometimes the forecast can change so much from one day to the next.

Looking further down the road, the 8-14 day outlook continues to suggest warmer and drier than normal conditions for OK heading into that last week of October.

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So, stay tuned and check back for updates.

Dick Faurot