Issued:  02/05/2012.

Highlights:

-  Showers are possible across the southeast 2/3rds of the state on Tuesday.  Snow is possible in the northwest and the panhandle.  Significant impacts are not expected.

-  Additional rain changes exist for Thursday and Friday, best potential will be in southern Oklahoma.

-  Temperatures will be in the mid 50s Monday, mid 40s Tuesday, low 40s on Wednesday, upper 40s Thursday – Friday, low 50s Saturday and upper 50s Sunday.

Probabilities:

-  Severe Thunderstorms in Oklahoma:  < 5%

-  Storm Chase:  < 5%

-  Winter Precip:  10%

Discussion:

Persistent western U.S. ridge will continue this week in a quasi rex block.  Weakening closed low, which undercut said ridge, will shift slowly eastward as it dampens.  While moisture is limited across the region, there should be enough to generate some light precipitation across the region.  Temperatures will be cold enough in the northwest for snow with rain elsewhere.  Another closed low will undercut the ridge and end up heading through Mexico by mid week.  Another upper system is progged to round the top of the ridge and dive southward and phase with the closed low over Mexico.  Not sure this will be the case, but the GFS seems to think it is a good idea.  ECMWF drops the circulation of the Gulf but either way, precip chances look slim but not zero.  Large closed low over eastern Canada seems to keep a steady supply of cool air moving into the region.  As such, temperatures will be lower this week than the past few but also much closer to normal.

Overall a quiet week is in-store for the region.  Models want to break down the western U.S. ridge later in the forecast period but I’m not convinced of that solution given how long the ridge has been around.

Issued:  01/29/2012.

Highlights:

-  Showers and a few thunderstorms are possible in eastern Oklahoma Tuesday afternoon and evening.  And again, Friday, although central Oklahoma may see some showers.  Snow maybe possible next weekend, but low confidence right now.

-  Temperatures will be in the mid 60s on Monday, upper 60s Tuesday, upper 50s Wednesday, mid 50s Thursday, low 50s Friday, near 40F Saturday, and low 40s Sunday.

Probabilities:

-  Severe Thunderstorms in Oklahoma:  5%

-  Storm Chase:  < 5%

-  Winter Precip:  15%

Discussion:

Zonal flow will continue for a few days before the CONUS pattern significantly amplifies.  Models are in decent agreement through 72 hours and then exhibit unusual disparity beyond that point.  Seemingly this is due to the forthcoming pattern change, which the models rarely handle well.  To that end, the forecast beyond Thursday is low confidence and high bust potential.

Shortwave trof will translate across the region on Tuesday in progressive zonal flow.  Said trof will induce a surface low, which is progged to drag at least low 50s dewpoints into the state by Tuesday afternoon.  Degree of heating and moisture return will provide at least a small opportunity for thunderstorms.  In general, showers are the more likely type.  Location of moisture return points to eastern Oklahoma being the primary area for any rain.  After Tuesday a weak Pacific cold front moves through, knocking highs down a little.  18z GFS is more robust with cooling for Wednesday, so this is reflected in my temps.

Upper system then forms near or just west of the region by Friday.  Models differ greatly on the development of this system along with subsequent movement and impacts.  Moisture availability remains high in the Gulf through much of the week, such that any system that can tap it will provide precipitation.  Persistence would argue for all rain no mater what, but climatology argues for snow chances.  So, that is the difficulty of forecasting this week.  The ECMWF’s pattern would seemingly favor snow next Saturday, to which I’ll just have to wait and see.  Special discussions may be required if a snow threat develops, hence the 15% chance.  It is a gamble, but we’ll see.

Went above MOS Monday/Tuesday, then with Wednesday/Thursday and below the remainder of the week.  As noted above, potential for colder temperatures Saturday and Sunday but I think the going numbers are cold enough for now.

Issued:  01/22/2012.

Highlights:

-  Showers are possible Tuesday into Wednesday, best chance is southern Oklahoma.

-  Temperatures will be in the upper 50s Monday, mid 50s Tuesday, upper 40s Wednesday, mid 50s Thursday, low 60s Friday, low 50s Saturday, and mid 50s Sunday.

Probabilities:

-  Severe Thunderstorms in Oklahoma:  < 5%

-  Storm Chase:  < 5%

-  Winter Precip:  < 5%

Discussion:

Powerful shortwave trof passing over Oklahoma this evening will continue moving east and then northeast the next few days.  Significant severe weather event underway across Arkansas and points east this evening.  NWS Little Rock issuing tornado warnings referencing large damaging tornadoes.  A Pacific cold front has moved into Oklahoma this evening and is progressing rapidly southeast as the surface low translates northeast away from the state.  Very warm temperatures today will become mild mid-winter temperatures on Monday in wake of the cold front.

Models consistent on develop a southwest U.S. closed low in the split flow across the U.S.  Said low show lumber slowly across Texas through Thursday and eventually get absorbed into the mean flow as a longwave trof develops across the northeast U.S.  Presence of 70F dewpoints in the Gulf, even in the wake of the current system, should provide plentiful moisture for the expected closed low Tuesday/Wednesday.  Model QPF values appear high for Oklahoma, especially the NAM.  The GFS is more reasonable and likely captures the expected areal extent of the rainfall.  Closed low leaves the region late Thursday with little in the way of impacts beyond then.  A cold front is expected to move through the region as the northeast system takes shape.  This will cool things off for the weekend.  For now, haven’t gotten aggressive on temperatures since winter 2011/12 has been mild so far.  At this point, GFS shows no Arctic intrusions through the remainder of January.

GFS temps look good and ECMWF agrees an the basic points of the forecast.

Issued:  12/26/2011.

Highlights:

-  Temperatures will be in the upper 40s Monday, mid 50s Tuesday, upper 50s Wednesday, near 60F Thursday, and low 60s Friday-Saturday, and mid 50s Sunday.

-  Happy New Year!

Probabilities:

-  Severe Thunderstorms in Oklahoma:  < 5%

-  Storm Chase:  < 5%

-  Winter Precip:  < 5%

Discussion:

Beautiful early winter week ahead for Oklahoma with temperatures a little above normal area wide.  Upper low that has been wobbling in west Texas the past few days is slowly lifting eastward and will be out of the region by late Tuesday.  After that the flow goes zonal with little in the way of impacts in Oklahoma.  Models show a few wind shifts nearby, but nothing significant.  ECMWF does show an eastern U.S. longwave trof developing just beyond this forecast period.  This would seemingly cool things off significantly if cold air builds in Canada.  At this time, precipitation looks nil across the region so all POPs zero through Sunday. GFS is a few days later regarding the eastern U.S. trof, so we’ll see.  Luckily I don’t have to make a call at this point.  However, Sunday could see a cool-off.

Went with GFS MOS through Saturday and then below on Sunday which seems in-keeping with forecasts to the northeast.

Issued:  12/18/2011.

*Significant Winter Weather Event for the Panhandle*

-  Blizzard Watch is posted for the Oklahoma panhandle with an upgrade to a Blizzard Warning likely for Monday into Tuesday.  Snowfall totals of 10-12 inches are likely with isolated ares up to 16 inches.

-  Winter Storm Watch is posted for far northwest Oklahoma with 3-6 inches of snow likely Monday into Tuesday.

-  Widespread rain is likely across much of Oklahoma Monday into Tuesday with some areas getting 1-2 inches.

-  A dusting of snow to one inch is possible from Oklahoma City north and west by Tuesday evening.

-  Temperatures will be near 50F Monday, falling on Tuesday into the mid-30s by late afternoon, mid 40s Wednesday – Thursday, near 40F Friday, mid 40s Saturday, and upper 40s Sunday.

-  Winter officially starts on Thursday, but the folks in the panhandle probably don’t care.

-  Merry Christmas to all!

Probabilities:

-  Severe Thunderstorms in Oklahoma:  < 5%

-  Storm Chase:  < 5%

-  Winter Precip:  50%

Discussion:

Wouldn’t be Christmas week in Oklahoma without a blizzard!  Models are in good agreement regarding the evolution of a closed southern stream shortwave low currently south of San Diego.  Said system is expected to drift eastward the next 12-18 hours and then start moving slowly northeast.  Models prog this system to move over the Texas panhandle and western Oklahoma into Kansas.  The general location of the heaviest snow track is well handled by the models.  As such, much of the Texas panhandle, Oklahoma panhandle, and southwest Kansas will get hit with at least 12 inches of snow.  Isolated amounts to 16 inches are also possible.  Elsewhere, a cold rain is expected.  Plenty of moisture is available, so model rainfall totals of 1-2 inches appear reasonable.  This should go a long ways against the current drought.  It will likely remove the D4 from Oklahoma as the panhandle has the only remaining area of D4.  Kept the winter precip at 50% due to the areal coverage of the event, even though it is high-end.

After this system passes, the pattern quiets down some.  There are two other systems progged to move over the region, but none are likely to cause any issues due to lack of moisture.  They will help keep the region cool much of the week.

NAM MOS was used through Wednesday and then undercut the GFS some through the rest of the week.

Issued:  12/11/2011.

Highlights:

-  Severe thunderstorms are possible on Wednesday, showers are possible on Tuesday.

-  Slight chance of rain/freezing rain on Saturday/Sunday.  Best potential for rain is southeast Oklahoma.

-  Temperatures will be in the low 50s Monday, upper 50s Tuesday, low 60s Wednesday, mid 50s Thursday, mid 40s Friday, low 40s Saturday, and upper 30s Sunday.

Probabilities:

-  Severe Thunderstorms in Oklahoma:  20%

-  Storm Chase:  < 5%

-  Winter Precip:  15%

Discussion:

Complex forecast this week with two at least low-end events and potential for a near medium-end event both times.  Model issues make forecasting quite difficult, even for the Wednesday event and certainly for next weekend.

Split flow will continue this week with southern stream systems diving south over California and then ejecting eastward across the region.  Two such systems are expected with the first Wednesday and the next during the weekend.  The first system has been consistently progged by all models to increase moisture across the state with low 60s likely by Wednesday afternoon.  The WAA pattern should result in widespread clouds across the state with heating seemingly minimal.  However, given the trend for 2011, severe weather prevails.  I’m not going to ignore the setup, although the primary threat will be large hail.  Medium-end events can occur in December, I believe it was December 12, 1991, which was a moderate risk.  Although nothing came of it due to high shear and very low thermo but SPC still did a tornado watch.  Upper system passes with little change in airmass.  Temperatures will be a little cooler absence WAA pattern.

Next upper system approaches the region next weekend and the models are in somewhat better agreement.  ECMWF and GFS keep swapping viewpoints with each other.  At this time the GFS’s progression is more typical of what we’ve seen this fall and what is expected next weekend.  The issue becomes the surface pattern, which none of the models seem to handle well.  The 500mb northern jet isn’t well defined and a significant cold air dump doesn’t seem likely.  However, temperatures will be below freezing during precipitation times next Friday-Sunday, such that freezing rain is possible.  Model soundings show the moisture in the lower few thousand feet of the atmosphere with little chance for snow.  At this time do not see a significant winter weather event, but a little of the freezing rain goes a long ways!  This is true for travelers, with minimal sun angle and surface heating.

Both setup will be monitored but at this juncture, special discussions are not anticipated.

Upper system clears the region on Sunday with quiet conditions for a few days.  GFS shows another southern stream system approaching the region around Christmas eve and no I’m not going there.

Followed the NAM somewhat on temperatures.  Wednesday will either be in the low 60s or near record breaking low 70s.  I’m sticking with the low 60s for now.  Beyond Wednesday went with general pattern, which agrees best with OUN and ECMWF.  GFS seems off and a little high in general.

Issued:  12/04/2011.

Highlights:

-  Showers are likely in the southeast part of Oklahoma tonight into Monday.

-  A dusting of snow is possible in western Oklahoma on Monday with flurries elsewhere.  The panhandle stands the best chance of snow with 1-2 inches likely.

-  Temperatures will be in the low 40s Monday, mid 30s Tuesday, low 40s Wednesday, mid 40s Thursday-Saturday, and upper 40s Sunday.

Probabilities:

-  Severe Thunderstorms in Oklahoma:  < 5%

-  Storm Chase:  < 5%

-  Winter Precip:  10%

Discussion:

The great snow storm of 2011 take three appears to be an illusion as all models have converged on higher QPF remaining well south of Oklahoma.   The displacement will also remove the QPF from the colder air, thereby not supporting snow in Oklahoma City or Tulsa.  Snow is likely in the Oklahoma panhandle where a Winter Weather Advisory is posted.

Current system prompting lots of showering activity in Texas and northeast as it shears eastward across the state.  This system will have little influence beyond today as it enters confluent flow and dampens.  Next southern stream shortwave trof will linger over New Mexico, which is progged to bring snow to the Oklahoma panhandle Monday into the evening hours.  This may also bring some snow to western Oklahoma, where a dusting is possible.  Farther east, flurries are about it.  The system will race northeast as the large closed low over northern Canada strengthens and a shortwave trof dives south over Wisconsin/Minnesota by midweek.  The main influence on Oklahoma will be a cold air pump that will continue much of the week.  This will keep temperatures below normal all week, with at least a few days in the 30s.  It will also usher in the coldest morning of the season when temperatures will likely reach the upper teens.  Mid-level pattern starts to flatten out by late week with a warming trend expected across Oklahoma.  No appreciable precipitation is expected after Tuesday across the state.  This would seemingly break the weekly rainfall events we’ve seen for the past month.  On the other hand, these have greatly reduced drought conditions across the eastern half of the state.  GFS does show a shortwave trof moving across Kansas next Sunday.  It does not develop QPF with this system and moisture appears to be lacking at this time.  However, should the system amplify or slow down, moisture may be available when it traverses near the region.  Either way, it is beyond this forecast period.

Generally went below MOS forecasts for the week, very much inline with NWS Norman.  Models are in decent agreement all week on the 500mb pattern.