nrgjeff

Well 2011 was a weak La Nina with snow in January and a warmer February. In no way would I ever joke about those tragic events. However I'm expecting an active severe wx season.

We are safe from severe for a while. However I love getting the thread going early and often! La Nina should get the South/Dixie going early and often as well. Plains would peter out if a quick transition to El Nino. It is all relative though. In the Plains even a BN severe May has opportunity. Last year is a good example. If one is flexible, I figure a good week will show up in May out in the Plains. I'm counting on it! Back here, looks quiet balance of January. We have cold snaps scheduled this weekend into early next week, and again at the end of the month and first of February if one believes the Weeklies. I figure the warmer middle and end of February (monthly forecast) would get severe going a little bit.

First, congratulations to all who enjoyed a rare big snow at the coast! Math, plus chemistry and physics if they offer it. Even something like Economics helps with the thought process of modeling a complex real world. CAD stands for cold air damming. It is when low level cold air banks up on the east side of the Appalachians. Look for surface high pressure to the northeast keeping a northeast or north wind fetch into the Carolinas. WAA aloft should not dislodge surface cold in that situation, but the surface high must keep pushing in cold air for winter precip. Retreating high press allows WAA at the surface and just regular rain. High resolution models are best, but all models still struggle with it. Finally CAD also occurs along other mountain ranges. The Rockies are notorious for the Plains. However it's normally snow not ice in the High Plains. There the challenge is how much to undercut MOS. Pacific Northwest can have nasty ice events when cold air drains down the Columbia River basin. It is not really CAD west of the mountains, but same principle.

Nashville NWS turned markedly more optimistic this package as 12Z guidance really dried out the column and PWs. Morristown got bullish this morning, issuing a forecast that is better than Nebraska climo. It is forecast time! Nashville and all of the Tennessee track should stay on the list of possibilities. We may get a lucky break with weak surface ridging and slightly rising 500 mb heights. Kentucky enjoys similar improvements to a point. None of this is a guarantee, but he region should stay on the short list.

KCMO area back through Nebraska has MCS risk, and it is too early to tell what time of day. However climo is night/morning. A lucky scenario would be subsidence behind any early MCS suppresses Cu. Then the partial phases keep Cu in check. Risk is lingering mid-level clouds. East Tennessee might edge out Nashville for a couple reasons. Lower elevations in the Tennessee Valley usually have slightly less Cu. Current NWP has a stationary front encroaching from the south, which must also be watched. North side of Totality in the Tennessee Valley (valley lower el.) is also farther from the said front (models verbatim). STL Carbondale Hopkinsville are kind of a crap shoot right now, anything from MCS hell to weak (but favorable) surface ridging. South Carolina depends on a boundary. Data and cell coverage will be awful to non-existent in Totality. We lose data on obvious dry line stakeouts. Everybody already knows the path of totality. So, I would not make target decisions based on cell networks. Forecast it right in the morning and use visuals for repositioning if needed. One could also call someone from a land-line for a nowcast.

Most of the eclipse sites, including Great American Eclipse, Eclipse2017.org and NASA, recommend not fumbling around with cameras and equipment. Even with practice 'dry runs' the total eclipse time is too short and precious. Still risk missing it. Plus professionals and media will get pictures. Finally, we will remember it better just watching from the corona to the sunset/rise on all of the horizons. From personal experience I remember best events I did not photograph. Saw a nearly overhead Aurora (northern lights) in Jasper, Canada 25 years ago and I still remember it like last night. Couple brief tornadoes I failed to photograph are the ones I remember best in my mind. So, my only equipment will be ISO/CE eclipse glasses and a shadowbox/pinhole viewer.

Like to base out of Winnipeg for Friday, but I will have to do so vicariously. Keep in mind Manitoba is excellent chase terrain both south and west of Winnipeg. One can even go east or north slightly without running into the forest or lakes. Friday issue could be MCS favored over discrete but we'll see. Saturday could be a break between waves before the Northwest trough settles in more Sunday. Then looks like pieces of energy eject Sunday and Monday, with the main trough Tuesday. Biggest problem I see is surface low and boundaries under the cap. ND is not capped but it is cool sector. Low and boundaries appear in SD. Still a few days for those details to iron out though. One bearish shift for chasers is the ensemble members are falling into line with operational models. Previously 30-40% of members were better than the ops. They were deeper with the trough, but no more. Odds of cap issues are up. One might be forced to chase the WF which requires a delicate balance between the cool sector and the cap. Tuesday the WF and quasi-DL could both go. However we know how main trough ejections have panned out the last couple years. Need to avoid the slop and/or going into the Minnesota trees. This is a good sequence for northern Plains chasers, but I'm not sure it is a travel set-up.

Euro is smokin' the GFS. Note the lead-in to Saturday. While the GFS and even NAM tried to get the LLJ going, though veered, Euro never really did so. Comparisons to 5/6/03 or 5/10/08 became invalid by morning as one realized no LLJ. While the GFS and 84hr NAM now want to get the late week going, beware of the Euro veto. Story is similar next week. GFS is bullish. Euro is skeptical. However Euro is at least introducing modest flow over the Plains. Second week of June may perk up also. I know that is a delay from the first week of June. However it is not unusual for crap patterns to go a little longer than forecast. If the CFS and Euro weeklies are right, the pattern could become more bullish second week of June.

State of the Chase Season still looks good. Synoptic season may be winding down, but quality set-ups will continue as we roll through the peak weeks of tornado climo. Later this week features modest WSW flow over a high CAPE environment. LLJ responds to upper waves a few days. Should be a sharp dry line and other boundaries. Details have yet to work out regarding the cap Thursday and LLJ over the weekend. Expect 1-3 good chase days. Late next week once again a trough may dig into the Rockies. Ensembles vary on timing but a majority have it dropping in there. Favorable pattern may be present into the week of June 5 as well. MJO and tropical Pacific are friendly to these weeks. Perhaps a couple good chase days both weeks of May 29 and June 5. Each week could also feature a sleeper day. Even if just normal activity, we have a friend in climo.

You are on the right track. Keep it simple weeks 3-4. Actually keep it simple week 2 also. GFS/Euro go out through week 2 but you've seen us make fun of the 11-15 day. Looks for a nice trough and the right pattern, not details. Weeks 3-4 are available on the CFS and Euro weeklies. That's an even quicker glance for the right pattern. First the GFS/Euro: I like a Rockies trough at 500/200 mb with SW/WSW flow over the Plains. SSW or S flow is not as favorable. If you are curious check 850 mb for a LLJ response S/SE there. It'll be there with a good trough, so maybe only check if a marginal trough. I prefer the downstream ridge over the Southeast, not the Upper Midwest, for several reasons including upper level winds and low level moisture. Just checking for wind direction with height and surface temps/dews. Weeks 3-4 are even simpler and quicker using the CFS/Euro weeklies. Most of the 500 mb presentations are height anomalies. While similar to the 500 mb heights chart, some cautions. What might look like a deep Southwest low could be a closed low, not ideal but can work. On the plus side, what looks like a meh northern Rockies trough could be favorable for subtle waves ejecting. The latter will start to look better on the GFS/Euro if the forecast holds. Finally I only use indices within a few days. Indices really just summarize the fundamentals. Turning with height and instability should yield good indices. Indices that incorporate directional shear should show local maximums along boundaries. Mismatches require looking back at the fundamentals. Another outflow better than the warm front? Any ongoing rain? Could be anything, but one has to figure the mismatch and adjust. If all lines up, a chase target is born.

Back half of of May is looking good for chasers who can forecast. Might be a couple big days, and maybe a big crap-out; otherwise, looks like a nice set-up picker's market. Closed lows (like this week) can and do produce like Wray Colorado. Week of the 15th, late that week near the Rozel anniversary, looks like a gorgeous open trough. Still fighting remnants of East trough, but the Plains can recover quickly in mid-May. Ensembles and weeklies hint at another trough week of May 22, again maybe later in the week. The later in May the better. Yes, it is hard to screw up late May barring a total debacle pattern.

If the current weather pattern holds, troughs Central and Southeast ridge, the Midwest fall/encore severe season could be at least somewhat interesting. PDO and ENSO analogs favor at least semi-persistence. Weeklies keep ridging East or Southeast with occasional troughs Central. Naturally Rockies troughs would be ideal for the Plains but most seem to be forming Central. Corn Belt can and occasionally does deliver in fall. I prefer September with the longer days but the above PDO/ENSO analogs have some trough west ridge east in October. My other reason for a September focus, is something other than the heat dragging on locally here in the Tennessee Valley. Living vicariously in the Midwest...

Welcome to the Forum and Central/West. Actually I find temperature forecasting quite interesting during the summer in California. One has to look at the marine layer from the coast into the valleys and the sea breeze later in the day. I find Southern California more forgiving. Some days a marine layer or sea-breeze forecast error can negate the other, saving a daily temperature forecast but the hourly may be a mess for a few hours. Northern California coastal valleys can be particularly unforgiving if one blows the marine layer and/or wind direction. Monsoon pattern also offers good forecast challenges. While temperatures do not make for good drama on a forecast forum, it is still interesting to follow. Otherwise, live vicariously in the Plains for some real weather action. Again welcome to the board and region.

Today should mark the beginning of a 7-10 day stretch of surprisingly good storm chasing so late in the season. Thank the Nino to Nina transition, reaching neutral by late spring. Jet stream is active from the Pac NW across the US/Canada border. SPC already has the box out for western Minnesota today. Distinct boundary offers a focal point for severe, perhaps tornadoes on a dominant cell. Wednesday looks like a good upslope day, from the boundary in northwest Kansas north into the upslope flow. Thursday should be active on the warm front in Iowa, but maybe sloppy. Friday could be the day-before-the-day in MT/ND. Saturday should be active with a defined system approaching North Dakota. LLJ responds to upper jet and moisture returns quite well. I would use Thursday to reposition for Friday, after the Wednesday target. One could argue Friday is the repo day if going from Iowa Thursday to ND Saturday. If I were really chasing I would try upslope Wednesday, repo Thursday, and be in MT/ND Friday. Don't forget the passport Fri/Sat. Sun/Mon the Saturday system lumbers northeast into Canada probably becoming meridional. Later next week another system is possible across the far northern US and/or on the Canadian border.

GFS ensembles and CFS weeklies should be available at NCEP or many free models sites. Euro ensembles and Euro weeklies usually require a subscription somewhere. Euro op is starting to show up on a few free sites though.

Both weeklies and some of the 11-15 day ensembles are starting to hint at a new trough in the Rockies. Some have it unseasonably south. Others have things northern Plains and Upper Midwest which is June Nino-ish. Either way a chaser has to like about a third of the way into June. North would be nice with smaller crowds.

Next week looks like some good storm chasing. Note I do not call for a big outbreak, but I see 3-4 chase days out of a 7 day stretch. Rockies trough is forecast to send out shortwaves for several days. Yes, sounds like SPC is teeing up. Sunday starts with short-wave ridging early but some southern stream jet energy pokes out over the Panhandles late. LLJ responds too. If enough moisture can return in time Sunday evening could be an appetizer. Monday and/or Tuesday should have some better moisture and wind shear, plus some surface boundaries to locally enhance SRH. Upper level wind fields are not particularly strong, but likely will be plenty for late May. Quality LLJ is forecast away from contamination. Plus no VBV is forecast. One can be reasonably confident that holds with WSW flow upstairs and open waves. If a stronger wave ejects Monday, then Tuesday could be an in between day. Tough to discern this far out. Wednesday or Thursday could go again. New shortwave is shown coming out sometime the middle of next week. Timing is variable run-to-run but the broad pattern is consistent. Perhaps Friday or Saturday something else comes out. For now I like Sunday-midweek.

Don't forget to check winds upstairs. Look for southwest winds at 500 mb and 200 mb; west is even better at 200 mb. Look for nearly straight south at 850 mb, SSE is even better. I wrote a lot more in the May 7-9 severe thread page 26. At any rate the 12Z GFS in on board with winds, and with low press and fronts in the central Plains. Lots of rain shown before peak heating, but it is days away...

In addition to climo improving for severe after April 15, a couple other reasons to be optimistic are noted. Pacific upstream situation should favor a transition to warmer zonal flow in the US, at first. Some of the weekly models hint a West trough later in April. Need to avoid the tear drop trash and get some real open troughs. Time will tell.

I agree with Andy. Models are probably too pessimistic due to clouds etc. However the system is very dynamic. It should over achieve. Look at the wind fields. SPC is right to go ENH for sure.

Ice storms are stressful at work so I voted no; otherwise, I would have voted light since it is pretty. On days you can get sunshine while ice is still on trees, it is a spectacular treat. Still, the day before was probably stressful at work, lol. Here is a detailed rank of weather for me: 1. Snow in the South - very special 2. Tornado chasing - never being chased 3. Hail, medium size - exciting but not damaging 4. Snow in the North - more routine 5. Sleet, with the hope of lightning 6. Straight line thunderstorm wind esp with good shelfie 7. Warm Sunshine 8. Dust storm - interesting but annoying 9. Heavy hoar frost or rime icing is pretty. 10. Freezing rain can be pretty. Worst weather: Flooding impacts too many lives too much. Low overcast is depressing with no precip.

Also, some model agreement is noted in the 11-15 day for a trough West ridge Midwest pattern. I'm talking end of August and first few days of September. Hints of both upper and low level jets responding is shown in the Plains some of the days. Northern stream staying active through the summer helps the case.

This week is well handled in the short-term thread. After perhaps a relatively quiet 6-10 day, always some little local events in June, things may become more active again the middle of June. MJO is forecast to perk up in Region 4-5 by some models. Others have the MJO going back to sleep. Region 4-5 is favorable for a Pac NW trough. Even the models that put the MJO back to sleep introduce the said trough late in the 11-15 day period. All 3 agree on the feature. Jet stream energy punches into the Pac NW. Downstream ridge is depicted over the Upper Midwest. All of the above is favorable for the northern High Plains. EDIT: June 4 probably needs to be added to the short-term thread dates. 12Z GFS/Euro both paint excellent chase days this Wednesday and Thursday. Moderate speed shear combines with high CAPE and quality low level turning. EML may finally limit junkvection and promote more chasable events.

Ian you are golden. GFS stands for curse words. Euro and Canadian keep warm sector in tact for next weekend. Both their ensemble products maintain the North American pattern into the 11-15. Euro weeklies and CFS maintain into early June. I think you get all that data, but just a reminder everything but a crappy op model is on your side. I'm reluctantly letting this weekend go based on long travel and odds. Tornadoes will verify today and tomorrow, but terrain issues are noted in NE/SD today. Tomorrow target is so diffuse I'm not betting a 700-800 mi drive on anywhere. However for those already out there, tomorrow will verify. Kansas sups may have issues with poor inflow and/or bad hodos. Eastern OK could go on the OFB with excellent shear but terrain could be an issue. Bust activity: Talimena Parkway is a gorgeous scenic drive. Lead up to Memorial Day could end up wet too. However I know this weekend is a mess. There is still hope for next. Much of next week a broad West trough is in place ejecting occasional short-waves. Each time a 250 mb jet comes out the LLJ at 850/925 mb responds. If a main target rainout, upslope would probably verify. It will work out one way or another. Late May climo favors tornadoes. Beyond that a recurving Pacific typhoon could have impacts. However Euro/Canadian ensembles do not echo GFS ens pattern change. Either the typhoon is not strong enough, or it just gets absorbed into a mid-latitude system within the already established buffet line of Pacific systems. Good to go!