Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/01/16

Area Forecast Discussion
National Weather Service Pueblo CO
1116 AM MDT TUE MAY 31 2016

.SHORT TERM...(Today and tonight)
Issued at 435 AM MDT Tue May 31 2016

...Showers and thunderstorms central/eastern mountains and adjacent
plains with some heavy rain possible...

Models continue to indicate that showers and thunderstorms will
develop and move south through southern Colorado today and tonight.
The area of widespread precipitation will primarily impact the east
slopes of the mountains and adjacent plains.  Areas to the west and
east of this area will see only isolated to scattered precipitation
and considerably lower precipitation amounts. The cold front that
will get things going is already moving south through El Paso County
at the present time. It will continue moving south early this
morning and be through all of southern Colorado by midmorning. Winds
will be northeasterly behind the front but will turn around to east
and finally southeast in most areas of the plains during the
afternoon. This will bring upslope forcing to areas along and near
the east slopes of the mountains. About the same time, an upper
disturbance will move through, providing lift from above during the
afternoon. The two forcing mechanisms will work together to lift a
moist and unstable airmass and get widespread showers and
thunderstorms going over the Pikes Peak Region during the late
afternoon.

A few showers are occurring, per radar, over eastern El
Paso County at the present time.  This is in a response to the front
moving through and lifting the air.  This just gives an indication
of how unstable the air is right now.  It`s hard to generate new
convection in southern Colorado during the predawn hours so the
airmass must be pretty unstable.  In any event, this activity may
come and go this morning but the really big show of precipitation
will hold off until later in the afternoon through the evening.
Early in this period, widespread showers and thunderstorms will get
going initially over the Pikes Peak Region and then spread south
through the course of the evening.  The severe threat doesn`t look
that great mainly due to a lack of shear.  The Storm Prediction
Center doesn`t even have southern Colorado outlooked for today.
Probably the main threat from storms this go around will be the
possibility of heavy rainfall.  The models are generating some
pretty hefty precipitation totals, which is usually an indication
that the model`s convective parameters are all being turned on. With
frontal forcing, an upper level trigger, adequate moisture, decent
instability and slow steering currents, heavy rain would certainly
seem reasonable.  Will have to watch for the possibility of some
flooding problems, especially over urban areas and burns scars.

For the western mountains and high valleys and also
the far eastern plains, showers and storms look to be much more
scattered with this event.  Precipitation amounts should be much
spottier and lower in these areas, with a much lower concern for any
flooding problems.  The rainfall will decrease from north to south
overnight, ending over the Pikes Peak Region by midnight and then
heading south of the New Mexico border by Wednesday morning.

Finally, it should be noted that the mountains above 10,000 feet
will see some more wet snow.  This time it looks likes generally 2
to 4 inches by Wednesday morning, with up to about half a foot or so
on top of Pikes Peak.

.LONG TERM...(Wednesday through Monday)
Issued at 435 AM MDT Tue May 31 2016

Wednesday...Colorado will be between two upper level low pressure
systems Wed morning, with a cold front rapidly sinking south into
New Mexico. Models agree on painting higher QPF and shower chances
along the southern Front Range through Wed morn as llvl upslope flow
strengthens. Expect scattered to likely pops over the higher
terrain, and isolated pops for the SLV and I-25 corridor, through
Wed eve. Wed will be the coolest day of the extended forecast
period, with max temps for most locations in the mid 60s to right
around 70 F.

Thursday through Monday...An upper ridge builds into the desert sw,
bringing much warmer and drier conditions over the weekend and into
the next work week. There will be the diurnal aftn and eve isolated
mt convection, but otherwise much of the area should remain dry,
save for some spillover across the I-25 corridor. Look for max temps
in the 80s to around 90 F for the plains, and 70s to near 80 F for
the high valleys. Fri is forecast to be the warmest day of the
extended. Moore

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1108 AM MDT Tue May 31 2016

Computer forecasts are showing a lot of inconsistent signals for
precip duration and timing today...lowering overall confidence in
extended periods of heavy rain. However, a period of moderate to
occasionally heavy rain is likely, particularly in the 21-03z
time frame for the I-25 corridor. Due to early clouds, instability
likely will be lower and prob of TS lower, so have removed TS from
FM groups, but left as VCTS. Could see a period of MVFR to
occasional IFR at KCOS and KPUB from 21-22Z through 06Z tonight,
with low cigs a possibility late tonight especially at KCOS. AT
KALS, should stay VFR with no precip but cannot rule out an
occasional shower. Rose

&&

.PUB Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...LW
LONG TERM...MOORE
AVIATION...ROSE



Area Forecast Discussion National Weather Service Pueblo CO 436 AM MDT TUE MAY 31 2016 .SHORT TERM...(Today and tonight) Issued at 435 AM MDT Tue May 31 2016 ...Showers and thunderstorms central/eastern mountains and adjacent plains with some heavy rain possible... Models continue to indicate that showers and thunderstorms will develop and move south through southern Colorado today and tonight. The area of widespread precipitation will primarily impact the east slopes of the mountains and adjacent plains. Areas to the west and east of this area will see only isolated to scattered precipitation and considerably lower precipitation amounts. The cold front that will get things going is already moving south through El Paso County at the present time. It will continue moving south early this morning and be through all of southern Colorado by midmorning. Winds will be northeasterly behind the front but will turn around to east and finally southeast in most areas of the plains during the afternoon. This will bring upslope forcing to areas along and near the east slopes of the mountains. About the same time, an upper disturbance will move through, providing lift from above during the afternoon. The two forcing mechanisms will work together to lift a moist and unstable airmass and get widespread showers and thunderstorms going over the Pikes Peak Region during the late afternoon. A few showers are occurring, per radar, over eastern El Paso County at the present time. This is in a response to the front moving through and lifting the air. This just gives an indication of how unstable the air is right now. It`s hard to generate new convection in southern Colorado during the predawn hours so the airmass must be pretty unstable. In any event, this activity may come and go this morning but the really big show of precipitation will hold off until later in the afternoon through the evening. Early in this period, widespread showers and thunderstorms will get going initially over the Pikes Peak Region and then spread south through the course of the evening. The severe threat doesn`t look that great mainly due to a lack of shear. The Storm Prediction Center doesn`t even have southern Colorado outlooked for today. Probably the main threat from storms this go around will be the possibility of heavy rainfall. The models are generating some pretty hefty precipitation totals, which is usually an indication that the model`s convective parameters are all being turned on. With frontal forcing, an upper level trigger, adequate moisture, decent instability and slow steering currents, heavy rain would certainly seem reasonable. Will have to watch for the possibility of some flooding problems, especially over urban areas and burns scars. For the western mountains and high valleys and also the far eastern plains, showers and storms look to be much more scattered with this event. Precipitation amounts should be much spottier and lower in these areas, with a much lower concern for any flooding problems. The rainfall will decrease from north to south overnight, ending over the Pikes Peak Region by midnight and then heading south of the New Mexico border by Wednesday morning. Finally, it should be noted that the mountains above 10,000 feet will see some more wet snow. This time it looks likes generally 2 to 4 inches by Wednesday morning, with up to about half a foot or so on top of Pikes Peak. .LONG TERM...(Wednesday through Monday) Issued at 435 AM MDT Tue May 31 2016 Wednesday...Colorado will be between two upper level low pressure systems Wed morning, with a cold front rapidly sinking south into New Mexico. Models agree on painting higher QPF and shower chances along the southern Front Range through Wed morn as llvl upslope flow strengthens. Expect scattered to likely pops over the higher terrain, and isolated pops for the SLV and I-25 corridor, through Wed eve. Wed will be the coolest day of the extended forecast period, with max temps for most locations in the mid 60s to right around 70 F. Thursday through Monday...An upper ridge builds into the desert sw, bringing much warmer and drier conditions over the weekend and into the next work week. There will be the diurnal aftn and eve isolated mt convection, but otherwise much of the area should remain dry, save for some spillover across the I-25 corridor. Look for max temps in the 80s to around 90 F for the plains, and 70s to near 80 F for the high valleys. Fri is forecast to be the warmest day of the extended. Moore && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 435 AM MDT Tue May 31 2016 A cold front is moving south through the eastern plains this morning. It has already moved through El Paso County and will be all the way south into New Mexico by midmorning. Behind the front, upslope flow will develop, helping to prime the atmosphere for the development of widespread showers and storms over the Pikes Peak Region during the afternoon, spreading southward through the evening. This will lead to the development of widespread MVFR, IFR and LIFR conditions through the afternoon and evening along and near the eastern mountains. Erratic thunderstorm winds, lightning and heavy rain will be the primary concerns with this system. The western mountains and high valleys and also the far eastern plains will see much less precipitation with this event. The KCOS and KPUB TAF sites will both likely see showers and thunderstorms move through with this system. There is a much lesser chance for KALS but there is still a chance. The initial onset of convection will be around noon. However, the more widespread and intense activity will likely hold off until late afternoon at KCOS and until evening at KPUB. For KALS, the best chance for weather moving through will be during the late afternoon and early evening. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...LW LONG TERM...MOORE AVIATION...LW
Area Forecast Discussion National Weather Service Pueblo CO 1105 PM MDT MON MAY 30 2016 .SHORT TERM...(This evening through Tuesday) Issued at 227 PM MDT Mon May 30 2016 ...Increased potential for thunderstorms for the SE Mts/Adjacent Plains Tuesday... Forecast area will be under weak forcing today ahead of trough axis out west connecting northern stream upper low moving through through northern U.S. Rockies and the desert southwest upper low. Showers and thunderstorms have fired off over the mountains...and are progged by models to continue eastward across the plains through the late afternoon/early evening. Surface low centered just north of KLHX has kept winds more southerly to southwesterly across the southern I-25 corridor and southern plains, and HRRR seems more inclined to mix out low level moisture today vs yesterday. However, where southeasterly winds maintain...could still see some lower 50 dew points...and CAPE values near 2000 J/kg through the early afternoon until mixing drops these off during the evening. Weak mid level winds today suggest deep layer shear may be on the weak side for organized supercell thunderstorms...but certainly a strong to marginally severe thunderstorm or two will be possible across the southeast plains to the east of KLHX. Main threat will be gusty winds to around 60 mph...but some hail up to 1 inch in diameter will also be possible with any initial intense updrafts. Activity will shift eastward into KS overnight. Northern stream upper Low will move eastward into the Dakotas tonight sending a cold front through southeast Colorado. Initially wind shift looks more thunderstorm outflow dominated this evening...but a secondary surge is expected after 09z with the main front. This will push cooler air into SE CO for Tuesday with winds shifting around from an easterly upslope direction during the afternoon. Question for Tuesday will be how much low level moisture will be retained behind the front and how much instability will be present. One of two scenarios could play out. If dew points drop off into the lower 40s this will significantly cut back on CAPE across the plains, but would likely maintain a narrow ribbon of up to 1000 J/kg of CAPE over the southeast mountains. However if surface dew points can maintain in the upper 40s and 50s...then this may be enough to keep 1000-1500+ J/kg of CAPE across much of the southeast plains. Still looks like main threat will be for widespread showers and thunderstorms for the southeast mountains initially during the afternoon with the plains being capped. . Best chance for a few strong storms or two will be over the mountains, particularly south of highway 50. This area is most likely to remain under low level theta-e axis with southern border counties also having some potential for some strong to marginally severe thunderstorm development in the afternoon. Will have to watch the burn scars in the SE mountains tomorrow afternoon as heavy rainfall from thunderstorms could produce some localized flash flooding for these more flood prone areas. For now think the risk is too localized to warrant flash flood watches at this point, but this will be re-assessed as the time frame gets resolved by higher res models. Snow levels will remain rather high through the day tomorrow, most likely above 11.5kft with higher peaks picking up a quick couple inches of snow during the afternoon. -KT .LONG TERM...(Tuesday night through Monday) Issued at 227 PM MDT Mon May 30 2016 ...Heavy Rain Possible Tue Night... Main concern in the extended comes early...Tue night...then things gradually settle down as a high amplitude ridge begins to build over the Rockies. Tue night...we get a good shot of upslope over the Ern CO Plains, as a 1020 ridge builds Over the High Plains on the backside of a shortwave system moving through the Dakotas and southern Canada. Concurrently...a weak low pressure system will track through southern AZ and NM. This will create a favorable upslope regime for our eastern mountains and I-25 corridor. NCEP models are in good agreement with between 0.5 and 1.0 inch of QPF over this region Tue night into Wed morning. Intensity level will be waning, so flash flood threat looks limited. However, still the possibility of some heavier cells impacting urban zones and burn scars, so will have to keep an eye on trend through the night into Wed morning. Heaviest amounts will be over Pikes Peak area and Wet mountains. Have boosted POPs to categorical for these zones, and spread POPs a bit farther to the east. Most of the I-25 corridor should see wetting rains. Far eastern Plains a bit more in question, but at least a chance of some rain for the areas farther east. For the mountains, snow levels may get down to 10000 feet or so, but heaviest snow accums will be above 11000 feet. Currently have about 4-8 inches of snow for the summit of Pikes Peak, and 3-6 for the Wets and Sangres. Considered an advisory for these high elevation zones, but given the high snow levels and relatively brief window of opportunity for higher QPF, will hold off. Travelers to the high country should be prepared for winter conditions through early Wed. Should see a bit of a respite late Wed morning into early afternoon, before another round of showers and a few storms hits Wed afternoon and eve, with persistent but weakening upslope through Wed night. This round does not look as heavy or widespread as the earlier one, however. After Wed, the upper ridge begins to build strongly over the Central Rockies, and temps will be on the increase over our area. Could see temps approach 90 degrees for the plains by the latter part of the week. Some moisture trapped under the ridge will keep a daily threat of showers and storms going each afternoon and eve, but primarily over the higher terrain and surrounding areas. Rose && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1104 PM MDT Mon May 30 2016 Winds are still expected to increase to around 15 to 25 knots form the north by early Tuesday morning as a front moves through. MVFR to local IFR CIGS are anticipated over the Palmer Divide region and will be capable of developing into the KCOS area by early Tuesday morning, depending on the strength of the northerly downslope winds. In addition, increasing threats of SHRA and TSRA are anticipated at the KCOS and KPUB taf sites from Tuesday afternoon into Tuesday night with CIGS expected to drop into the IFR category at times during this time-frame. At KALS, generally VFR conditions should be noted during the next 24 hours, although isolated showers and thunderstorms will be possible, primarily during the afternoon and evening hours. && .PUB Watches/Warnings/Advisories... NONE. && $$
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
607 AM CDT MON MAY 30 2016 ...AVIATION UPDATE... .SHORT TERM...(Today and Tonight) Issued at 256 AM CDT MON MAY 30 2016 08Z water vapor imagery shows little chance to the overall pattern from 24 hours ago. There is still an upper low over southern CA and an upper trough moving across the northern Rockies leaving somewhat zonal and relatively weak flow over KS. At the surface, high pressure remains over the southern MS river valley with low pressure along the lee of the Rockies. This is allowing for a moist airmass to remain over the central plains. A conditionally unstable airmass is expected once again this afternoon with temps warming into the lower and mid 80s while dewpoints remain in the mid 60s. This should be good for CAPE values around 2000 J/kg. However 0-6 KM shear remains weak given the weak synoptic flow over the region. So once again the weather will be driven more by mesoscale features, and confidence of where exactly forcing or lift for storms will come from is low. With this in mind, have 30 to 40 percent POPs through the afternoon for possible scattered convection. If storms are able to form, they will once again pose a risk for hail as there looks to be plenty of instability (although the NAM looks to be overdone with dewpoints and hence the CAPE prog). But organized severe storms would be limited by the weak deep layer shear. Highs this afternoon are based on the RAP and NAM forecast soundings mixing the boundary layer to around 800MB and yesterdays highs making the upper 80s in some locations. If cloud cover is limited to the afternoon, the forecast could again be a degree or two on the cool side. Any afternoon convection should fall apart this evening with the stabilization of the boundary layer. Although models show a shortwave and frontal boundary moving into north central KS during the early morning hours Tuesday. The addition of some dynamics to the moist airmass should only increase chances for precip. And with most guidance showing showers and thunderstorms along the frontal boundary, the forecast has increasing POPs after 06Z from northwest to southeast across the forecast area. There does not appear to be a significant wind shift with any cold air advection until after 12Z Tuesday. Therefore lows are expected to be mild as southerly low level flow maintains a moist airmass. So have lows in the lower and middle 60s. The one caveat would be if a decent cold pool formed from convection with the front. This could cause lows to be several degrees cooler. Later shifts can look at this again. .LONG TERM...(Tuesday through Sunday) Issued at 256 AM CDT MON MAY 30 2016 On Tuesday, the mid level shortwave trough enters the western high plains. A cold front extending southward will push east through the region, providing the convergence and lift for widespread convection throughout the day. Timing from guidance still varies somewhat similar to yesterday`s model trends. The NAM appears to be the slow outlier and the ECMWF/GFS in similar agreement with the heaviest rainfall being in the afternoon. Ample moisture in place with PWAT values near 1.65 inches is about 150 percent of normal for this time of year. Moderate rainfall is likely at times which may produce a quick inch of rain, in addition to localized flooding and river flooding. Mid-level winds are not particularly strong, suggesting this boundary may move a bit slower, increasing the flood potential especially for north central areas. While shear profiles remain weak at 15-20 kts, ample instability with steep mid level lapse rates will support updrafts capable of producing large hail and damaging wind gusts through early evening. There may be lingering showers and thunderstorms over east central Kansas on Wednesday, but these should clear out as dry northwest flow enters the region. Highs will fall back Wednesday and Thursday into the 70s with lower humidity values and more comfortable conditions. Overnight lows will generally be in the 50s under clear skies. The upper ridge over the western CONUS begins to amplify by late week, essentially trapping the southern plains under a closed low and continual rainfall. Dry northwest flow centers over northeast Kansas where Gulf moisture is cutoff by the southern system. A mid level trough is progged to track south and east towards the Great Lakes during this time, dropping another cold front through for next weekend. Models are still inconsistent on available moisture and lift as the boundary comes through so have continued with dry pops. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning) Issued at 607 AM CDT MON MAY 30 2016 Have a VFR forecast with no mention of TS for now since there is low confidence in where afternoon convection might occur. The patchy ground fog is expected to quickly dissipate this morning leaving VFR conditions for the rest of the day. Models are hinting at some possible BR after midnight tonight. The NAM has a tendency to overdo the boundary layer moisture, so will let later shifts see if models continue to show low level saturation tonight. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Wolters LONG TERM...Prieto AVIATION...Wolters
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
243 PM CDT MON MAY 30 2016 .SHORT TERM...(This afternoon through Tuesday) Issued at 243 PM CDT Mon May 30 2016 Our focus is on the potential for severe thunderstorms through this evening, especially in south central ND. The 18 UTC Bismarck sounding sampled relatively steep mid-level lapse rates near 7.5 C/km, contributing to MLCAPE around 1000 J/kg despite increasing cloud cover. The sounding also revealed 0-6-km bulk wind shear just over 30 kt, sufficient for organized storms, but likely favoring multi-cellular modes, especially given a small weakness in the wind fields just above 700 MB. The 19 UTC surface analysis places a surface low just north of Bismarck, with a warm front extending east of the low from near Washburn to Carrington, and a cold front south across central Morton and Grant Counties. That demarcates the severe risk going forward, as supported by recent convection-allowing model guidance. The 18 UTC sounding revealed an uncapped air mass, and as a result convection and the related cloud cover is still posing some issues to the potential for severe convection. However, very recent visible satellite imagery shows clearing over Grant County near the cold frontal zone, which may enable more intense updrafts to form in the next hour or two. That`s in line with convection-allowing model output that still suggests a line of storms with hail and wind potential will move eastward near and south of I-94 from around Bismarck to Jamestown between 20 and 03 UTC. On Tuesday, the low pressure system will have occluded and the surface to 500 MB circulation is forecast to become stacked in north central ND. Showers and embedded, non-severe storms are simulated by guidance to be wrapping around the north and west sides of the stacked low, impacting much of western and north central ND. There is some uncertainty in the southward extent of the shower activity, with the ECMWF and 12 UTC NAM slightly more robust with QPF to the south of Highway 200 than the GFS. Nonetheless, those models are in relatively good agreement and a blend of them supports widespread PoPs over 60 percent over much of western and central ND, save for across the southern James River valley where a mid-level dry slot will be in play. Note that there is still a non-zero risk of weak funnels near the stacked low over north central ND, but diagnostic output from the 12 UTC guidance suggests that the low-level CAPE-VGP setting will not favor cold core tornadoes. Conceptually, the stacked low scenario doesn`t favor cold core tornadoes, either, as it reduces low-level baroclinicity and vorticity somewhat. .LONG TERM...(Tuesday night through Sunday) Issued at 243 PM CDT Mon May 30 2016 Lingering shower activity will gradually end Tuesday night and early Wednesday as the stacked low pressure system slowly moves east-northeast into southwest Ontario. The 12 UTC models are in relatively good agreement suggesting that mid-level flow should lose its cyclonic nature during the day Wednesday as that low departs and 500-MB heights rise a bit in its wake. There may be a low-end shower potential in central ND until those heights do begin rising by afternoon, but confidence in any showers is low. The key message we want to convey in the long term is a warming trend that will commence by late week. The multi-model consensus calls for highs to warm from the 60s F on Wednesday to the 70s F Thursday, and upper 70s and lower 80s F Friday through Monday as a stout 500-MB ridge takes shape over the intermountain west and exerts its influence downstream across the northern Plains. The deterministic and ensemble guidance displays low spread with the ridge axis, but the amplitude of downstream flow differs, as the 00 and 06 UTC GFS simulations are generally deeper with a low in the Great Lakes region by late weekend. A deeper low would favor greater potential for somewhat cooler air to be advected into ND in the general northwest flow aloft. CIPS analogs applied to the 00 UTC GFS ensemble reflect that possibility, offering no strong signal as to whether temperatures will be above or below normal. However, the non-GFS guidance supports less amplitude to the low over the Great Lakes, favoring the warmer regime that`s also the main influence on our blended-model-driven forecast. CIPS analog output strongly favors below-normal precipitation in the period centered on this weekend, especially in western ND, so we have a mainly dry forecast in play. However, the 00 and 12 UTC GFS and NAM, and to a somewhat lesser extent the ECMWF, suggest that a mid-level shortwave trough will cross the region Thursday night and Friday, offering some shower and thunderstorm potential in that time frame. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 243 PM CDT Mon May 30 2016 Widespread showers and thunderstorms will spread east out of western and across central ND this afternoon and evening. Local MVFR to IFR conditions are expected. Some storms may be severe with large hail and damaging winds southwest and south central. Widespread showers and embedded thunderstorms will continue into Tuesday. MVFR to IFR ceilings are likely Tuesday in northwest and north central ND, and they are possible over southwest and south central ND, too. && .BIS Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...CJS LONG TERM...CJS AVIATION...CJS
Area Forecast Discussion National Weather Service Grand Forks ND 638 AM CDT MON MAY 30 2016 .UPDATE... Issued at 635 AM CDT Mon May 30 2016 No significant changes made this update period. && .SHORT TERM...(Today through Tuesday) Issued at 200 AM CDT Mon May 30 2016 forecast concerns will be severe potential tonight and rain duration. Models still differ on surface low position however high resolution models supporting farther north solution. Otherwise overall message similar with severe potential tonight. Today will start out sunny with increasing southerly flow/moisture flux during the afternoon. Surface low to organize over the northern high plains and will be location of convective initiation. Farther south solution would have convection also developing along E-W boundary along the ND/SD border area where the northern solution keeps convection farther west. With model differences there is some uncertainty as to when convection will reach our FA so did not make significant changes to pops. Should be sufficient solar along with warm advection to get temperatures a few degrees warmer than Sunday highs. Main action will be tonight as surface low and related convection shifts east into the region. Bulk shear not overly impressive and best upper support lags back into the western/central dakotas. However strong low level forcing and sufficient cape/instability for severe storm threat. Slight risk area expanded north and justified with some model showing farther north solution. Surface low will reside over the northern fa on Tuesday. Dry slotting will limit best rain chances to the northern fa. As a result coolest temperatures will be across the north with temperatures close to average across the south. .LONG TERM...(Tuesday night through Sunday) Issued at 200 AM CDT Mon May 30 2016 Low becomes stacked Tuesday night across the northern valley region so only a slow eastward propagation expected. This will slowly shift wrap around rain band slowly east overnight to the valley region. low will pull out Wednesday with best rain chances over the ne fa. Cooler column and clouds will hold temperatures well blo average. Wednesday to Saturday night...Models have become consistent with robust short wave trough moving across the northern plains to start the extended period. Stacked low pressure system centered over the valley will bring a cool...damp start to June with clouds and showers lingering into the afternoon especially in NW MN...highs in the 60s. Thursday and first half of Friday will be dry as 500mb ridging and NW flow aloft bring weak high pressure to the Northern Plains. The next CHC for convection arrives Friday PM into Saturday as sfc low and upper support track across northern Manitoba dragging a boundary across the FA. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) Issued at 635 AM CDT Mon May 30 2016 With exception of BJI which has localized FG, VFR conditions expected atleast through mid afternoon. Any lower cigs there after will be associated with TSRA. At this time still some uncertainty on arrival time. && .FGF Watches/Warnings/Advisories... ND...None. MN...None. && $$ UPDATE...Voelker SHORT TERM...Voelker LONG TERM...JK/Voelker AVIATION...Voelker
Area Forecast Discussion National Weather Service Grand Forks ND 1153 PM CDT SUN MAY 29 2016 .UPDATE... Issued at 1153 PM CDT Sun May 29 2016 Minimal changes made with this update. UPDATE Issued at 954 PM CDT Sun May 29 2016 Added a slight chance of showers in far SE ND late tonight/early tomorrow morning. HRRR and HopWRF tipped the scales to mentioning something down near the SD border. NAM/GFS have some FGEN in that area...but limited CAPEs. Just enough to produce a shower or two on the ND side. UPDATE Issued at 712 PM CDT Sun May 29 2016 A quiet evening is expected across the forecast area. The latest HRRR model hints at showers and perhaps a thunderstorm along the ND/SD border late tonight/early tomorrow morning. The latest NAM also hints at this although MU-CAPE values supporting elevated convection stay to the south and west through 12z...except in the devils lake basin. Will continue with a dry forecast tonight for now and consider the new NAM and HRRR runs for next update. && .SHORT TERM...(This evening through Monday night) Issued at 329 PM CDT Sun May 29 2016 Main forecast challenge will be severe potential for areas along and south of the Interstate 94 corridor on Monday afternoon and Monday evening. As for tonight, the cumulus field is already showing signs of thinning. There are a few showers left from Mahnomen to Detroit Lakes, but these should not last too much longer. Drier air continues to move in from the west, with the dew point at KDVL already at 41F. With the drier air moving in, not expecting fog formation tonight. Monday will start out nice, but storms will increase over the central or western Dakotas by afternoon. SPC day 2 outlook has areas along and south of the Interstate 94 corridor in a marginal risk, with Sargent County ND in a slight risk. This event still a day away, so confidence not great at the moment in timing or placement of the tstm development. There is a lot of variation yet in the models, with the ECMWF slower than the American models. Thinking that storms will fire over the western or central Dakotas in the afternoon and move eastward and affect this FA during the late afternoon or evening. Models do show good agreement in another widespread pcpn event, with a good one to two inches for most of the FA. Models also agree on showing most of the pcpn rotating northward later Monday night, with drying working into portions of far southeast ND. .LONG TERM...(Tuesday through Sunday) Issued at 329 PM CDT Sun May 29 2016 On Tuesday the dry slot remains over southeast ND and portions of west central MN, with the main pcpn band along and north of highway 200. As the sfc low lifts NE Tue night into Wed, the pcpn will slowly turn to lighter wraparound bands. For Wed night through Sunday...Surface high will be dropping into northern valley behind an upper ridge that should dry things out Wed night and keep it dry on Thursday...with slightly cooler temperatures generally in the 60s...with lower 70s in southeastern ND. Return flow then sets up Thu night with a frontal system moving into the area early Fri morning, bringing a chance for showers and thunderstorms through Sat morning. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1153 PM CDT Sun May 29 2016 A shower or two may exist south of KFAR around sunrise. There is a low probablity that any showers would make it as far north as KFAR. Most should stay closer to the SD border. Added thunderstorms for Monday night in all TAFs. Expecting a large area of thunderstorms extending NW to SE generally by evening. There will likely be MVFR or even IFR cigs beyond this TAF period, first at KDVL and then moving east. && .FGF Watches/Warnings/Advisories... ND...None. MN...None. && $$ UPDATE...Knutsvig SHORT TERM...Godon LONG TERM...Godon/Speicher AVIATION...Knutsvig Area Forecast Discussion National Weather Service Pueblo CO 1147 PM MDT TUE MAY 31 2016 .SHORT TERM...(This evening through Wednesday) Issued at 251 PM MDT Tue May 31 2016 ...Good chance of rain for most of the plains tonight... Currently...showers and thunderstorms building steadily over the eastern mountains. Main shortwave is now moving into southeast WY and the NE panhandle, while another upper low is steadily moving east through southern AZ and N Mexico. Dew points are in the upper 40s to lower 50s over the plains. Respectable low level moisture, weak to moderate upslope, and upper forcing from the two low pressure systems will combine for a good chance of precip tonight, especially over the eastern mountains and plains. There was considerable inconsistency in the 12Z model runs for timing and placement of greater QPF, but high res short term guidance such as the HRRR is starting to congeal on a general solution for late this afternoon and tonight. Looks like a wide band of moderate to occasionally heavy precip will develop over the Pikes Peak region over the next several hours, then translate SEWD across the I-24 corridor and Plains this evening and overnight, then linger across the Raton region and SE plains Wed morning. Main concern will be the potential for localized flooding, although precip rates should not be all that intense. Early cloud cover has limited instability, with CAPE currently in the 500-1000 j/kg over the region this afternoon. Best chance for precip over the KCOS to KPUB area will be late this afternoon through early evening, before the heavier precip shifts to the SE later tonight. QPF amounts generally in the 0.25 to 0.5 inch range, with some localized inch or more amounts. Will also see some higher elevation snow late this afternoon through tonight, mainly above 11000 feet. Summit of Pikes Peak could see around 4-6 inches of snow through Wed morning, and tops of Wets and Sangres an inch or two. Continued cool on Wed with lingering cloud cover through the early morning hours, and persistent showers to the south and east. A strong upper ridge will begin to build to our west tomorrow, but a weak shortwave rounding the east side of the ridge will spark another round of showers and storms Wed afternoon, primary over the mountains and far eastern Plains. The I-25 corridor potentially could stay dry tomorrow afternoon. High temps will range from the upper 60s to lower 70s for the plains, and 50s-60s for the mountains and high valleys. Rose .LONG TERM...(Wednesday night through Tuesday) Issued at 251 PM MDT Tue May 31 2016 Wed night through Fri an upr level ridge wl be building ovr the SW U.S. and the forecast area wl be on the front side of this ridge. There wl still be enough mstr ovr the area Thu for isold to sct afternoon and evening showers/tstms ovr and nr the mtns. On Fri it generally looks like just some isold showers/tstms could develop ovr the mtn areas. On Thu, high temps are expected to be around average, and then on Fri highs wl be warmer than average. Sat the upr ridge wl be centered over the Great Basin. A front is expected to drop south through the southeast CO plains on Sat. It looks a little more active Sat afternoon and evening, with scattered showers/tstms over the mtn and high valley areas, and possibly spread out over the I-25 corridor as well. High temps on Sat are expected to be a little above average. On Sun an upper level low is expected to be centered over central CA, while the forecast area wl still be under NW flow aloft. On Mon that upper low is expected to move eastward into srn NV. There wl still be enough mstr ovr the area both days for at least scattered showers/tstms ovr and nr the mtns, with isold chances ovr the southeast plains. Highs both days are expected to be above average. Tue that low is expected to weaken and become an open wave. There are some model differences as to where this system wl track, with the ecmwf being farther west and north than the gfs which brings it into wrn CO Tue afternoon. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1135 PM MDT Tue May 31 2016 Primary concern tonight will be MVFR, IFR, and potential LIFR conditions due to low CIGS at KPUB and KCOS. Evening rainfall across KPUB and KCOS has moistened the boundary layer considerably priming the atmosphere for low stratus development. At KPUB, weak upslope flow in a moist environment will allow for IFR and LIFR CIGS to develop between 07-13Z. Latest high res models suggest a brief window of opportunity for fog development at KPUB between 09-11Z, but suspect winds will remain just strong enough to prevent fog from forming. At KCOS MVFR to IFR CIGS are likely between 07-13Z. Weak downslope winds out of the NNE will likely keep LIFR conditions from developing. KCOS and KALS will begin to see VCTS starting around 19Z tomorrow as storms form over the higher terrain and drift eastward towards the terminals. Lukinbeal/Petersen && .PUB Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...ROSE LONG TERM...28 AVIATION...PETERSEN
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
332 AM CDT WED JUN 1 2016 .SHORT TERM...(Today and Tonight) Issued at 317 AM CDT WED JUN 1 2016 Surface obs show high pressure building into northern KS and a diffuse frontal boundary somewhere across east central KS. An area of low pressure was noted over the northern plains where a closed upper low was spinning. Water vapor also indicated an upper low over the southwest. With this split flow over the central plains and a general lack of organized forcing, think the surface ridging will be the main factor in the forecast for today and tonight. Most model guidance suggests the poorly defined front at the surface and 850MB should set up just south of the forecast area with the deeper moisture axis over southern KS and southern MO. Models show any low level convergence along the boundary to remain south of the forecast area. Therefore with no forcing think chances for precip are about 10 percent over Coffey and Anderson counties and have removed the mention of precip from the forecast. By this afternoon and evening, continued dry air advection should continue to push the higher probabilities for precip south. So dry weather is expected today and tonight. Have trended highs a little warmer as the RAP and NAM forecast soundings show the boundary layer mixing to around 800MB. 850MB temps around 14C would support highs in the mid 70s but think reasonable insolation should bump temps up a little more so the forecast has highs around 80. The weak surface ridge of high pressure is progged to move across the forecast area tonight. This should allow for some radiational cooling due to the light winds and mostly clear skies. With this in mind, lows are forecast to be in the middle and upper 50s. .LONG TERM...(Thursday through Tuesday) Issued at 317 AM CDT WED JUN 1 2016 Most of the mid range and extended forecast period will be characterized by weak flow aloft therefore seeing little in the way of lift to cause too much change in the weather pattern. So, have kept with a mostly dry pattern regarding POPs. Focus period for any slight chance for light showers and perhaps a few claps of thunder will be late Friday and early Saturday morning. Trimmed back POPs a bit south of I-70 mainly as the North Pac Low shoots in over the Northern Plains and deepens as a speed max dives toward the Upper MS Valley. As the upper low deepens, the associated trough looks like it will have enough energy to develop a surface cool boundary that will get pushed along and into northeastern KS. Much like the recent cool boundary that created mostly clouds rather than precip over the forecast area, do expect that weak forcing with this system over the forecast area will result in much the same. It does appear that all guidance hints at this possibility as the signal is to decrease QPF. Feel comfortable in the reduction of POPs over northeast KS at this time since this seems to have been a continuous trend from previous model runs. The trend with the low over the southwest CONUS is to eventually become an open wave over South TX vicinity. From this point into the weekend, expect that heights gradually rise over the forecast area and weak flow aloft continues with perhaps northern stream flow remaining north of the forecast area for at least a while looking forward. Any shortwaves trying to break down the ridging over the area appear to be short lived. No consistency on changes at this time, so have left a dry forecast. Expect temps to generally rise steadily into the mid to potentially upper 80s by middle of next week. Meanwhile, lows will rise into the mid 60s. Judging by the normal values, this puts both highs and lows near the 5-10 degree above normal range. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday Night) Issued at 1145 PM CDT TUE MAY 31 2016 VFR conditions expected. North winds are increasing on both observations and models in the lower levels. Along with a likely steady flow of at least some cirrus, will remove BR mention. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Wolters LONG TERM...Drake AVIATION...65 Area Forecast Discussion National Weather Service Pueblo CO 1147 PM MDT TUE MAY 31 2016 .SHORT TERM...(This evening through Wednesday) Issued at 251 PM MDT Tue May 31 2016 ...Good chance of rain for most of the plains tonight... Currently...showers and thunderstorms building steadily over the eastern mountains. Main shortwave is now moving into southeast WY and the NE panhandle, while another upper low is steadily moving east through southern AZ and N Mexico. Dew points are in the upper 40s to lower 50s over the plains. Respectable low level moisture, weak to moderate upslope, and upper forcing from the two low pressure systems will combine for a good chance of precip tonight, especially over the eastern mountains and plains. There was considerable inconsistency in the 12Z model runs for timing and placement of greater QPF, but high res short term guidance such as the HRRR is starting to congeal on a general solution for late this afternoon and tonight. Looks like a wide band of moderate to occasionally heavy precip will develop over the Pikes Peak region over the next several hours, then translate SEWD across the I-24 corridor and Plains this evening and overnight, then linger across the Raton region and SE plains Wed morning. Main concern will be the potential for localized flooding, although precip rates should not be all that intense. Early cloud cover has limited instability, with CAPE currently in the 500-1000 j/kg over the region this afternoon. Best chance for precip over the KCOS to KPUB area will be late this afternoon through early evening, before the heavier precip shifts to the SE later tonight. QPF amounts generally in the 0.25 to 0.5 inch range, with some localized inch or more amounts. Will also see some higher elevation snow late this afternoon through tonight, mainly above 11000 feet. Summit of Pikes Peak could see around 4-6 inches of snow through Wed morning, and tops of Wets and Sangres an inch or two. Continued cool on Wed with lingering cloud cover through the early morning hours, and persistent showers to the south and east. A strong upper ridge will begin to build to our west tomorrow, but a weak shortwave rounding the east side of the ridge will spark another round of showers and storms Wed afternoon, primary over the mountains and far eastern Plains. The I-25 corridor potentially could stay dry tomorrow afternoon. High temps will range from the upper 60s to lower 70s for the plains, and 50s-60s for the mountains and high valleys. Rose .LONG TERM...(Wednesday night through Tuesday) Issued at 251 PM MDT Tue May 31 2016 Wed night through Fri an upr level ridge wl be building ovr the SW U.S. and the forecast area wl be on the front side of this ridge. There wl still be enough mstr ovr the area Thu for isold to sct afternoon and evening showers/tstms ovr and nr the mtns. On Fri it generally looks like just some isold showers/tstms could develop ovr the mtn areas. On Thu, high temps are expected to be around average, and then on Fri highs wl be warmer than average. Sat the upr ridge wl be centered over the Great Basin. A front is expected to drop south through the southeast CO plains on Sat. It looks a little more active Sat afternoon and evening, with scattered showers/tstms over the mtn and high valley areas, and possibly spread out over the I-25 corridor as well. High temps on Sat are expected to be a little above average. On Sun an upper level low is expected to be centered over central CA, while the forecast area wl still be under NW flow aloft. On Mon that upper low is expected to move eastward into srn NV. There wl still be enough mstr ovr the area both days for at least scattered showers/tstms ovr and nr the mtns, with isold chances ovr the southeast plains. Highs both days are expected to be above average. Tue that low is expected to weaken and become an open wave. There are some model differences as to where this system wl track, with the ecmwf being farther west and north than the gfs which brings it into wrn CO Tue afternoon. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1135 PM MDT Tue May 31 2016 Primary concern tonight will be MVFR, IFR, and potential LIFR conditions due to low CIGS at KPUB and KCOS. Evening rainfall across KPUB and KCOS has moistened the boundary layer considerably priming the atmosphere for low stratus development. At KPUB, weak upslope flow in a moist environment will allow for IFR and LIFR CIGS to develop between 07-13Z. Latest high res models suggest a brief window of opportunity for fog development at KPUB between 09-11Z, but suspect winds will remain just strong enough to prevent fog from forming. At KCOS MVFR to IFR CIGS are likely between 07-13Z. Weak downslope winds out of the NNE will likely keep LIFR conditions from developing. KCOS and KALS will begin to see VCTS starting around 19Z tomorrow as storms form over the higher terrain and drift eastward towards the terminals. Lukinbeal/Petersen && .PUB Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...ROSE LONG TERM...28 AVIATION...PETERSEN
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
541 AM CDT WED JUN 1 2016 ...AVIATION UPDATE... .SHORT TERM...(Today and Tonight) Issued at 317 AM CDT WED JUN 1 2016 Surface obs show high pressure building into northern KS and a diffuse frontal boundary somewhere across east central KS. An area of low pressure was noted over the northern plains where a closed upper low was spinning. Water vapor also indicated an upper low over the southwest. With this split flow over the central plains and a general lack of organized forcing, think the surface ridging will be the main factor in the forecast for today and tonight. Most model guidance suggests the poorly defined front at the surface and 850MB should set up just south of the forecast area with the deeper moisture axis over southern KS and southern MO. Models show any low level convergence along the boundary to remain south of the forecast area. Therefore with no forcing think chances for precip are about 10 percent over Coffey and Anderson counties and have removed the mention of precip from the forecast. By this afternoon and evening, continued dry air advection should continue to push the higher probabilities for precip south. So dry weather is expected today and tonight. Have trended highs a little warmer as the RAP and NAM forecast soundings show the boundary layer mixing to around 800MB. 850MB temps around 14C would support highs in the mid 70s but think reasonable insolation should bump temps up a little more so the forecast has highs around 80. The weak surface ridge of high pressure is progged to move across the forecast area tonight. This should allow for some radiational cooling due to the light winds and mostly clear skies. With this in mind, lows are forecast to be in the middle and upper 50s. .LONG TERM...(Thursday through Tuesday) Issued at 317 AM CDT WED JUN 1 2016 Most of the mid range and extended forecast period will be characterized by weak flow aloft therefore seeing little in the way of lift to cause too much change in the weather pattern. So, have kept with a mostly dry pattern regarding POPs. Focus period for any slight chance for light showers and perhaps a few claps of thunder will be late Friday and early Saturday morning. Trimmed back POPs a bit south of I-70 mainly as the North Pac Low shoots in over the Northern Plains and deepens as a speed max dives toward the Upper MS Valley. As the upper low deepens, the associated trough looks like it will have enough energy to develop a surface cool boundary that will get pushed along and into northeastern KS. Much like the recent cool boundary that created mostly clouds rather than precip over the forecast area, do expect that weak forcing with this system over the forecast area will result in much the same. It does appear that all guidance hints at this possibility as the signal is to decrease QPF. Feel comfortable in the reduction of POPs over northeast KS at this time since this seems to have been a continuous trend from previous model runs. The trend with the low over the southwest CONUS is to eventually become an open wave over South TX vicinity. From this point into the weekend, expect that heights gradually rise over the forecast area and weak flow aloft continues with perhaps northern stream flow remaining north of the forecast area for at least a while looking forward. Any shortwaves trying to break down the ridging over the area appear to be short lived. No consistency on changes at this time, so have left a dry forecast. Expect temps to generally rise steadily into the mid to potentially upper 80s by middle of next week. Meanwhile, lows will rise into the mid 60s. Judging by the normal values, this puts both highs and lows near the 5-10 degree above normal range. && .AVIATION...(For the 12Z TAFS through 12Z Thursday Morning) Issued at 541 AM CDT WED JUN 1 2016 Dryer air moving in and a general lack of forcing should lead to VFR conditions through the period. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Wolters LONG TERM...Drake AVIATION...Wolters Area Forecast Discussion National Weather Service Pueblo CO 1147 PM MDT TUE MAY 31 2016 .SHORT TERM...(This evening through Wednesday) Issued at 251 PM MDT Tue May 31 2016 ...Good chance of rain for most of the plains tonight... Currently...showers and thunderstorms building steadily over the eastern mountains. Main shortwave is now moving into southeast WY and the NE panhandle, while another upper low is steadily moving east through southern AZ and N Mexico. Dew points are in the upper 40s to lower 50s over the plains. Respectable low level moisture, weak to moderate upslope, and upper forcing from the two low pressure systems will combine for a good chance of precip tonight, especially over the eastern mountains and plains. There was considerable inconsistency in the 12Z model runs for timing and placement of greater QPF, but high res short term guidance such as the HRRR is starting to congeal on a general solution for late this afternoon and tonight. Looks like a wide band of moderate to occasionally heavy precip will develop over the Pikes Peak region over the next several hours, then translate SEWD across the I-24 corridor and Plains this evening and overnight, then linger across the Raton region and SE plains Wed morning. Main concern will be the potential for localized flooding, although precip rates should not be all that intense. Early cloud cover has limited instability, with CAPE currently in the 500-1000 j/kg over the region this afternoon. Best chance for precip over the KCOS to KPUB area will be late this afternoon through early evening, before the heavier precip shifts to the SE later tonight. QPF amounts generally in the 0.25 to 0.5 inch range, with some localized inch or more amounts. Will also see some higher elevation snow late this afternoon through tonight, mainly above 11000 feet. Summit of Pikes Peak could see around 4-6 inches of snow through Wed morning, and tops of Wets and Sangres an inch or two. Continued cool on Wed with lingering cloud cover through the early morning hours, and persistent showers to the south and east. A strong upper ridge will begin to build to our west tomorrow, but a weak shortwave rounding the east side of the ridge will spark another round of showers and storms Wed afternoon, primary over the mountains and far eastern Plains. The I-25 corridor potentially could stay dry tomorrow afternoon. High temps will range from the upper 60s to lower 70s for the plains, and 50s-60s for the mountains and high valleys. Rose .LONG TERM...(Wednesday night through Tuesday) Issued at 251 PM MDT Tue May 31 2016 Wed night through Fri an upr level ridge wl be building ovr the SW U.S. and the forecast area wl be on the front side of this ridge. There wl still be enough mstr ovr the area Thu for isold to sct afternoon and evening showers/tstms ovr and nr the mtns. On Fri it generally looks like just some isold showers/tstms could develop ovr the mtn areas. On Thu, high temps are expected to be around average, and then on Fri highs wl be warmer than average. Sat the upr ridge wl be centered over the Great Basin. A front is expected to drop south through the southeast CO plains on Sat. It looks a little more active Sat afternoon and evening, with scattered showers/tstms over the mtn and high valley areas, and possibly spread out over the I-25 corridor as well. High temps on Sat are expected to be a little above average. On Sun an upper level low is expected to be centered over central CA, while the forecast area wl still be under NW flow aloft. On Mon that upper low is expected to move eastward into srn NV. There wl still be enough mstr ovr the area both days for at least scattered showers/tstms ovr and nr the mtns, with isold chances ovr the southeast plains. Highs both days are expected to be above average. Tue that low is expected to weaken and become an open wave. There are some model differences as to where this system wl track, with the ecmwf being farther west and north than the gfs which brings it into wrn CO Tue afternoon. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1135 PM MDT Tue May 31 2016 Primary concern tonight will be MVFR, IFR, and potential LIFR conditions due to low CIGS at KPUB and KCOS. Evening rainfall across KPUB and KCOS has moistened the boundary layer considerably priming the atmosphere for low stratus development. At KPUB, weak upslope flow in a moist environment will allow for IFR and LIFR CIGS to develop between 07-13Z. Latest high res models suggest a brief window of opportunity for fog development at KPUB between 09-11Z, but suspect winds will remain just strong enough to prevent fog from forming. At KCOS MVFR to IFR CIGS are likely between 07-13Z. Weak downslope winds out of the NNE will likely keep LIFR conditions from developing. KCOS and KALS will begin to see VCTS starting around 19Z tomorrow as storms form over the higher terrain and drift eastward towards the terminals. Lukinbeal/Petersen && .PUB Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...ROSE LONG TERM...28 AVIATION...PETERSEN