Desert Photography

 I'm spending a week in the Sedona, Arizona region and started a new desert section in my photography portfolio. Check it out here.

Lake Michigan Horizontal Shearing Instability Snow Band

 A lake effect snow band occurred along the long axis of Lake Michigan during 19 January 2024, and conditions were apparently favorable for the development of numerous mesovortices that would spin up and propagate toward the south shore with Indiana. Surface observations showed north-northwest winds across the western half of the lake gusting from 20-30 kt, while winds were nearly calm on the east side of the lake. A strong gradient in velocity was thus present near the middle of the lake in the east-west direction. Such a gradient likely aided in a horizontal shearing instability causing the lake effect snow band to roll up into fairly large meso-vortices. A feature associated with these vortices was the enhancement in radar reflectivity and thus snowfall rates along the northwest side of the area of rotation, and decrease in reflectivity/snowfall rates along the immediate southeast side of rotation.

KLOT radar reflectivity from the morning of 19 January 2024 showing the lake effect band moving from north to south across Lake Michigan and rolling up into individual vortices.

Mid-day two panel plot of reflectivity and storm-relative velocity observed by the KLOT radar. Images are annotated in order to show the rotation present within the lake effect snow band, both in the reflectivity plot on the left and storm-relative velocity plot on the right. Also note that reflectivity/snowfall rates are locally highest along the northwest side of the area of rotation.

Surface observations and composite reflectivity showing the lake effect snowband with mesoscale vortices, as well as the strong gradient in wind speed going from the west side of the lake to the east side.

HRRR model output showing strong gusty northwest winds over the west side of Lake Michigan and nearly calm winds on the east side which yielded an intense gradient in wind speed near the middle of the lake favorable for possible horizontal shearing instability.

A RAP model sounding valid at 1900 UTC 19 January 2024 near the location of the lake effect snow band. Steep low-level lapse rates and a saturated airmass favored convectively enhanced lake effect snow, with CAPE most certainly higher after the sounding is modified at the surface for the actual lake temperature and dewpoint.

Underground Railroad // Pioneer Home // Balbec, Indiana

 Amy Schreiber and myself braved brutal arctic air plus wind and headed south to Balbec, Indiana in order to visit a historic pioneer home that was a stop on the Underground Railroad. I spent 15 minutes max outdoors in the brutal cold, and I can only imagine the misery many endured in similar cold but with few if any modern options for warmth. The cabin that hosted many during their journey north to Canada was stark, wooden floors, a fire place, and an upstairs loft. There was an old water pump outdoors, a couple of ancient looking trees, and a historic marker within view of Highway 1. The map location of the site is here.

Wabash River Origins and Fort Recovery, Ohio

 Amy Schreiber and myself were on an early January mission to find the origins of the Wabash River in west-central Ohio. Our mission was a success...the origin of the river that traverses all of Indiana starts off as a very small stream in the middle of corn fields a few miles south of Fort Recovery, Ohio. After braving a few minutes outdoors exploring the river in cold bitter windswept Ohio winter weather, we headed north into Fort Recovery. The fort that General Mad Anthony Wayne erected has been partially recreated. This is also the site of the greatest defeat in United States military history due to some brilliant battle strategy conjured up by Little Turtle and his unified tribal army. In addition, the site of the fort is also the reference point of the 1800 Greenville Treaty Boundary Line, the exact site of the survey point marked by a small circular plate (see image below). A lot of early American history, and pre-history, is packed into this region of Ohio...definitely worth a visit. [The origin point of the Wabash River is here. Fort Recovery is here.]

Light to Moderate Snowfall Across Northern Indiana: 9 January 2024

A zone of strong low to midlevel warm air advection aided in moderate precipitation rates across the northern half of Indiana during the pre-sunrise hours of January 9th, 2024. The airmass in the lowest couple of kilometers hovered very close to freezing, with surface temperatures at Fort Wayne slightly above 32F. Nevertheless, strong upward vertical motion through a deep layer favored moderately heavy snowfall rates that overcame the marginal low-level temperatures. However, the period of heavier snowfall was short-lived, as above freezing air near 850 mb quickly spread north across Indiana, bringing an end to snow and initiating a quick transition to rain.

A shield of precipitation forced by intense low to midlevel warm air advection spread north across northern Indiana a few hours before sunrise during 9 January 2024. The narrow band of higher reflectivity moving north marks the transition from snow to the north and rain to the south.

Composite radar reflectivity with surface observations overlaid. Note the marginal surface temperatures within the zone of heavier precipitation over northern Indiana. Dewpoints in the 20s likely aided in enhancing wet bulb cooling that maintained a sufficiently cold low-level airmass for snow.

Surface wet-bulb temperatures ranging from 32 to 33F over northern Indiana were marginally cold enough for snow.

850 mb temperatures show a robust transition from sub-freezing to above-freezing air going from north to south across the Midwest.

850 mb temperature advection.

Short term model guidance, such as the RAP (shown above) did a good job predicting a band of 2-5 inch snowfall occurring across northern Indiana during the early morning hours of 9 January 2024.

RAP forecast sounding valid 10 UTC 9 January 2024 near Fort Wayne, Indiana. Note the saturated isothermal layer hovering near 0C from the surface to around 850 mb. Strong ascent was also present within the -10 to -20 C layer, likely forced by intense low to midlevel warm air advection inferred by the strongly veering wind profile.

A few inches of snow observed in southern Fort Wayne, Indiana at around 5 AM on 9 January 2024.

Western Kansas Blizzard: 8 January 2024

An upper low centered over the Southern High Plains was focusing strong synoptic-scale ascent over western Kansas during the afternoon of January 8, 2024. In addition, a quasi-stationary frontal boundary was positioned from the Oklahoma Panhandle northeast across eastern Nebraska. An intense low to midlevel temperature gradient was oriented along the front and was yielding strong frontogenesis that was evident in radar reflectivity as a narrow contracting band of precipitation. Lightning was also observed over southwest Kansas in a zone of EPV reduction. Very strong ascent augmented by frontogenesis combined with reduced midlevel stability was subsequently resulting in heavy snowfall over western Kansas, and that snow was collocated with a post-frontal northerly barrier jet yielding gusts from 30 to 60 kt. Blizzard conditions with visibility reduced to a quarter mile or less were observed, and temperatures were in the teens and 20s. The threat to humans and livestock is substantial in those conditions.

A classic frontogenetic snowband was situated from west-central Kansas northeast to just east of McCook, Nebraska.

Surface observations with regional radar reflectivity and frontal analysis overlaid.

925-850 mb frontogenesis.

850 mb wind speed. Note the intense post-frontal northerly barrier jet over western Kansas.

RAP sounding valid 20 UTC 8 January 2024 over western Kansas. A classic frontogenetic signature is seen in the vertical wind profile, with strong north-northeasterlies in the low-levels rapidly veering to southerly above 600 mb.

Hanging Rock on the Wabash - Indiana

 Amy Schreiber and myself explored an assortment of waterfalls in the vicinity of the Wabash River in central Indiana during late December. We also made time to visit Hanging Rock, which is an exposed fossilized coral reef that towers 50-100 feet above the Wabash. This feature also served as a landmark and meeting place for tribes of the past. Hanging Rock is located here.

Significant "All Hazards" Winter Storm January 8th-10th

 Ensemble and deterministic model guidance is maintaining a consistent significant "all hazards" winter storm signal that migrates eastward across the central and eastern United States during the January 8th-10th period. By 12Z on the 9th, a vertically stacked deep-layer low is forecast by most guidance to be centered in the vicinity of southwestern Missouri. This will aid in the development of a pronounced surface cyclone and frontal wave advancing from Texas east across the Gulf Coast states. In addition, wind fields will be strong at all levels and upward vertical motion will be substantial. The operational GFS shows relatively high values of boundary-layer theta-e spreading north across the warm sector of the previously mentioned surface wave, and mid-level lapse rates will be fairly steep (>7 C/km), thus there is the potential for MLCAPE values to range from 1000-2000 J/kg, which is large for January. However, it's uncertain whether the warm sector will experience daytime surface insolation due to widespread low-level cloudiness, and that will likely impact convective mode evolution and possible tornado intensity. Nevertheless, current forecast wind fields are exceptionally favorable for long-track violent tornadoes within the previously mentioned surface warm sector (particularly far eastern Texas, southern Louisiana, southern Mississippi, and southern Alabama and adjacent Georgia and Florida panhandle), with mean 0-1 km streamwise vorticity >0.02 s-1.

Farther north, a mainly sub-zero deep-layer airmass will be in place from roughly the mid-Mississippi Valley northeast across the Great Lakes. In addition, very strong upward vertical motion is forecast to occur in the vicinity of a northeastward migrating 700 mb low. Thus, ingredients will likely be favorable for a band of heavy snowfall, the exact location obviously being a function of the near-surface freezing line and mesoscale ascent focused near the previously mentioned 700 mb low. Elsewhere in between the band of heavy snow to the north and severe weather to the south, heavy rain, gusty gradient winds, and perhaps embedded elevated thunderstorm activity will be probable.

Four-panel plot of 500 mb wind/heights valid 12Z 1/9/2024.

Four-panel plot of 850 mb wind/heights/temperature valid 12Z 1/9/2024.

GFS surface theta-e valid 09Z 1/9/2024. Note the northward flux of higher theta-e across southeast Mississippi and immediate surrounding region which is the approximate location of the surface warm sector.

GFS model forecast sounding representing the severe storm/tornado environment valid 09Z 1/9/2024 in southeast Mississippi.

GFS 6-hour snowfall accumulation valid 00Z 1/10/2024.

GFS model forecast sounding representing the heavy snow environment located across Michigan valid 21Z 1/9/2024.